Prion Diseases in Dromedary Camels (CPD) 2022 Review
Neuropathology of Animal Prion Diseases
Published: 21 March 2021
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3.6. Prion Diseases in Dromedary Camels (CPD)
Dromedary camel or Arabian camel (Camelus dromedarius) is one of the three surviving species of camel and represents 94% of the world camel population. They are present in Northern and Eastern Africa, the Middle East, part of Asia and also in Australia. In the latter country, the presence of this species is related to animals originally imported from British India and Afghanistan for use in transport and construction, since mid-19th century [153].
The Bactrian camel (Camelus bactrianus), distributed mainly in Central Asia, and the Wild Bactrian camel (Camelus ferus), distributed in Northwest China and Mongolia, are the remaining two species of the family Camelidae [153]. They are of extreme importance due to their milk and meat, constituting an excellent food resource in arid and semi-arid climates [154].
Recently, a prion disease, named Camel Prion Disease (CPD), was first identified in dromedary camels in Algeria in 2018 [32] and then in Tunisia, in the Tataouine region, in 2019 [155]. The first dromedary camel cases, from a Saharian population in Ouargla (Southeastern Algeria) were identified in a routine antemortem inspection when brought for slaughter at the Ouargla abattoir, one of the largest in Algeria [32].
The animals arrived at the abattoir showing weight loss, behavioural abnormalities (observed in the early stages of disease) and also neurologic signs, such as tremors, aggressiveness, hyperreactivity, typical down and upward movements of the head, uncertain gait, ataxia of the hind limbs, falling and difficulty in rising from a lying position. According to local breeders, the disease could extent from 3 to 8 months and its thought to be present since the 1980s [32]. The affected animals had the same PRNP genotype showing 100% nt identity with the PRNP sequence already reported for dromedary camels [32].
Histopathology showed spongiform change, gliosis and neuronal loss in symptomatic animals but not in asymptomatic ones. Vacuolation was always seen in the neuropil but it could also be found in neuronal bodies. Confluent vacuoles were rarely observed. Neurodegenerative changes were consistent in the grey matter of subcortical brain areas (striatum, thalamus, midbrain, and pons) while rare in the white matter (Figure 5). The cortical brain areas and the cerebellum were variably involved presenting vacuolation in cingulate, piriform, and frontal cortices and only in the molecular layer of the cerebellum. The cervical medulla showed no spongiform changes [32].
In medulla oblongata, moderate vacuolation was observed, particularly in the vestibular and the olivary nucleus; the nucleus of the solitary tract and the hypoglossal nucleus were less often affected [32].
Immunohistochemical staining showed PrPSc deposition associated with vacuolation but also in areas less or not affected by spongiosis such as the nucleus of the solitary tract, the hypoglossal nucleus, the pyramidal cells of the hippocampus, the granular layer of the cerebellum, the Purkinje cells and several white matter areas.
The most frequent detected PrPSc types were intraneuronal, intraglial, synaptic/punctuate (equivalent to fine granular), perineuronal, linear, and perivascular (Figure 6). In pons and medulla oblongata, an atypical intracellular pattern was observed in which PrPSc filled the whole cytoplasm. PrPSc was absent in the brain of the asymptomatic dromedary [32].
PrPSc was present in all lymph nodes collected from one animal, suggesting extraneuronal pathogenesis and so, a potential excretion that may result in transmission between animals [32] (Figure 5).
The western blot characterization has shown that dromedary camels’ PrPSc is less glycosylated than those of CS. It presents a monoglycosylated dominant PrPSc and an apparent molecular weight slightly higher than CS and clearly higher than BSE and sheep passaged BSE [32].
The origin of CPD is still unknown but it may be associated with the exportation of meat and bone meal from BSE affected countries and subsequent contamination of animal feed. However, dromedaries are usually not fed commercial feed. On the other hand, these animals are frequently grazed with sheep and goats; hence, CPD’s origin could be related to scrapie. However, there is no scrapie surveillance program in Algeria and no cases were reported so far. To clarify these questions, bioassays are being performed in rodent models for an exhaustive strain characterization [32].
Upon detection of this new disease, the OIE acted to study its impact and to decide if it would be considered an emerging disease. For that, two ad hoc groups were consulted: one for the evaluation of BSE risk status and the other about camelids. As there are still few data concerning this disease it was not possible to conclude about its impact on animal and public health. However, surveillance in countries with affected or not dromedary’s population is crucial for collecting information needed for risk assessment.
Two projects are ongoing for the coordinated surveillance of CPD. One launched by the CAMENET (Camel Middle East Network) and the other by the EFRAN (Enhancing Research for African Network) [155].
The importance of ongoing international surveillance for Creutzfeldt–Jakob disease
| June 2021 | volume 17
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Camel prion disease. A novel prion disease, termed camel prion disease (CPD), was detected in three symptomatic dromedary camels in Algeria in 2018 (ref.252). The PrPres signature of CPD did not match that of scrapie or BSE252, which raised several concerns. First, the disease was presumed to have arisen naturally; transmission of a prion disease from another species was not suspected, as no BSE had been detected in local cattle and naturally arising scrapie is not known to be present in Algeria252. Second, camels were the first non-ruminant species, other than humans, to naturally manifest prion disease, thus extending the spectrum of prion diseasesusceptible animals252. Third, PrPSc was detectable in peripheral lymphoid tissues, raising concern for horizontal transmission252. Last is the possibility that the causative agent could undergo alteration on passage through an intermediate host, enhancing transmissibility, as discussed above.
Another camel with CPD was identified in Tunisia in 2019 (ref.253). Concerns now exist over the prevalence of this previously unrecognized transmissible spongiform encephalopathy, and recognition of cases will likely increase as a result of heightened awareness254. The global dromedary population is in the millions, with large populations in Africa and the Middle East, as well as in Australia255,256. The potential for human exposure to CPD is substantial; however, transmission studies will be necessary to determine whether the disease has zoonotic potential. Substantial constraints on resources as well as geopolitical instability in the regions affected by CPD pose major challenges; many affected countries do not have national CJD surveillance programmes.
Camel Prion Disease Umberto Agrimi – Remesa 26-27 June 2019
Camel Prion Disease
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Umberto Agrimi – Remesa 26-27 June 2019
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According to the FAO live animals statistics, the worldwide camel population is ~35 million heads (FAO, 2019), most of which are in Somalia, Sudan, Niger, Kenya, Chad, Ethiopia, Mali, Mauritania, and Pakistan.
Camels have represented and still represent the means of subsistence for millions of families who live in the most hostile ecosystems on the planet.
Partly due to climatic changes, areas of camel rearing are expanding, especially in Africa (Faye et al., 2012). During the past years, the camel farming system has evolved rapidly and improved substantially (Faye et al., 2014).
The emergence of a prion disease in a farmed animal species of such importance requires a thorough risk assessment for implementing evidence-based policies to control the disease in animals and minimize human exposure.
CPD: what we know
• CPD is a novel prion disease
• It has been reported in Algeria (Prof. Baaissaa Babelhadj) and Tunisia (Prof. Abdelkader Amara Ecole Vétérinaire, Sidi Thabet)
• It affects adult animals
• In the Ouargla Region (Algeria), where CPD has been first identified, its incidence is rapidly and progressively increasing (Baaissa, personal communication)
• The involvement of the lymphoreticular system suggests CPD is an infectious prion disease
• Preliminary reults suggest that the CPD prion strain is different from scrapie and BSE
CPD: what we don’t know
• What is the origin of CPD?
• What is his geographic distribution?
• How does CPD transmit?
• Does a genetic resistence to CPD exist in the dromedary species?
• What is the risk for humans?
• …...
Three main areas of research and intervention:
• Getting knowledge on CPD geographic distribution
• Investigating the possible existance of genetic factors modulating CPD susceptibility/resistance
• Establishing diagnostic capacity and a surveillance system on neurological symptoms, at local level
Italy has got excellent capacity in the field of prion diseases and through the European Reference Laboratory and the OIE Reference Laboratory for prion diseases would be pleased to collaborate with local Competent Authorities and official laboratories and to provide technical scientific support.
Immunohistochemical examination of lymphoid tissues
Cervical, prescapular, and lumbar aortic lymph nodes were collected from one symptomatic animal.
Immunohistochemistry revealed PrPSc deposition in primary and secondary follicles from all lymph nodes.
WOAH Designated ADAFSA’s Veterinary Labs as First Collaborating Centre for Camel Diseases in Middle East
Subject: OIE Camel Prion Disease
OIE Bulletin
Camel prion disease: a possible emerging disease in dromedary camel populations?
The identification of a new prion disease in dromedary camels in Algeria and Tunisia, called camel prion disease (CPD), extends the spectrum of animal species naturally susceptible to prion diseases and opens up new research areas for investigation.
Camel prion disease was identified in 2018 in adult camels showing clinical signs at the ante mortem inspection at slaughterhouses in the region of Ouargla (Algeria), and in 2019 in the region of Tataouine (Tunisia). It adds to the group of existing animal prion diseases, including scrapie in sheep and goats, chronic wasting disease (CWD) in cervids and BSE (mainly in bovines). The detection of a new prion disease in the dromedary population requires attention and investigation needs to be carried out to assess the risks of this disease to animal and public health. As of today, very limited epidemiological information is available to assess the prevalence, geographical distribution and dynamic of the transmission of the disease.
Based on the clinical signs suggesting prion disease, CPD seems to have occurred in 3.1% of the dromedaries brought to the abattoir in Ouargla. Pathognomonic neurodegeneration and disease specific prion protein (PrPSc) were detected in brain tissue from three symptomatic animals (source:
In May 2019, the OIE received a report from Tunisia on a single case of a 12-year-old slaughtered dromedary camel showing neurological signs confirmed as CPD by the Istituto Superiore di Sanità (ISS) based in Italy.
©B. Babelhadj/University Kasdi Merbah, Algeria
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Is camel prion disease transmissible in natural conditions?
The involvement of lymphoid tissue in prion replication, observed both in the Algeria and Tunisia cases, is suggestive of a peripheral pathogenesis, which is thought to be a prerequisite for prion shedding into the environment. As with other animal prion diseases, such as scrapie and CWD, in which lymphoid tissues are extensively involved and horizontal transmission occurs efficiently under natural conditions, the detection of prion proteins in lymph nodes is suggestive of the infectious nature of CPD and concurs to hypothesise the potential impact of CPD on animal health. No evidence is currently available with which to argue for the relevance of CPD for human health. However, no absolute species barrier exists in prion diseases and minimising the exposure of humans to prion-infected animal products is an essential aspect of public health protection. As for the relationship between CPD and other animal prion diseases, preliminary analyses suggest that CPD prions have a different molecular signature from scrapie and BSE.
Actions on the follow up of CPD
Since the first description of CPD, the OIE promoted discussions on the impact of this new disease through the OIE Scientific Commission for Animal Diseases (Scientific Commission). The Scientific Commission consulted two OIE ad hoc Groups, one on BSE risk status evaluation of Members and the other on camelids. It analysed the information available from the Algeria and Tunisia cases to evaluate if CPD should be considered an ‘emerging disease’ based on the criteria listed in the Terrestrial Animal Health Code1 .
The OIE Scientific Commission noted that limited surveillance data were available on the prevalence of CPD and that the evidence was not sufficient to measure, at that time, the impact of the disease on animal or public health. Therefore, it was concluded that, with the current knowledge, CPD did not currently meet the criteria to be considered an emerging disease. Nonetheless, it was emphasised that CPD should be considered as a new disease not to be overlooked and called for the collection of further scientific evidence through research and surveillance in the affected countries and in countries with dromedary camel populations to measure the impact of the disease. As new scientific evidence becomes available, the OIE Scientific Commission will reassess whether this disease should be considered as an emerging disease.
The worldwide camel population is ~35 million head (FAO, 2019), 88% of which is found in Africa. The camel farming system is evolving rapidly, and these animals represent vital sources of meat, milk and transportation for millions of people living in the most arid regions of the world. This makes it necessary to assess the risk for animal and human health and to develop evidence-based policies to control and limit the spread of the disease in animals, and to minimise human exposure. As a first step, the awareness of Veterinary Services about CPD and its diagnostic capacity needs to be improved in all countries where dromedaries are part of the domestic livestock.
At the regional level, CPD was first discussed in the 18th Joint Permanent Committee of the Mediterranean Animal Health Network (REMESA) held in Cairo, Egypt, in June 2019 where an expert 1 a new occurrence in an animal of a disease, infection or infestation, causing a significant impact on animal or public health resulting from a) a change of a known pathogenic agent or its spread to a new geographic area or species, or b) a previously unrecognised pathogenic agent or disease diagnosed for the first time www.oiebulletin.com
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from ISS, Italy, shared the knowledge available on the new disease with the 15 REMESA Member Countries. The discussion highlighted the need to strengthen surveillance systems in order to collect epidemiological data to inform the risk assessments. The results of these risk assessments will support the implementation of evidence-based policies to manage the risks in both animals and humans.
CPD was recently discussed atthe 15thConference of the OIE Regional Commission for the Middle East in November. During this conference, the CAMENET (Camel Middle East Network) launched a wide ranging proposal for training, coordinated surveillance and research on CPD. In addition, the ERFAN (Enhancing Research for Africa Network), a platform aimed at enhancing scientific cooperation between Africa and Italy, during its 2nd ERFAN meeting for North Africa, presented a project on CPD with the objective of increasing CPD coordinated surveillance in North Africa.
The OIE, through its Reference Laboratories for prion diseases, and by involving the above scientific initiatives, is keeping a close watch on the evolution of the disease to gather scientific evidence and to allow a proper and more thorough assessment of the risk associated with this novel disease.
◼ December 2019
Working Document on Camel Prion Disease (CPrD) 14/09/2020
Content: I. Introduction II. Camel prion disease III. Case definition IV. Epidemiological surveillance V. Biosafety VI. Capacity building VII. Early warning and response VIII. Risk factors IX. Knowledge Gaps X. References
I. Introduction
Camel prion disease (CPrD) is the last disease described in the family of prion diseases [1]. To date, it has been recognized only in Middle East of Algeria and in the neighboring region of Tunisia [2]. However, there are no known other initiatives of prion diseases surveillance in camels worldwide. CPrD might actually be limited to the already known geographic area in North Africa or spread undetected in other Countries, as a consequence of the movements of dromedaries along trans-Saharan commercial routes, the import/export trade flows of living animals and the traditional extensive and nomadic rearing systems.
According to the discussions in recent meetings of REMESA and OIE which indicated the need to extend the knowledge on CPrD spread in Countries where camels are extensively reared and considered as a part of the domestic livestock [3], and according to the initiative from CAMENET member countries to assess the risk in the CAMENET region, this working document aims to provide countries with the main technical and scientific knowledge necessary to implement surveillance programs on camel prion disease in its own territory. Basic information contained in this document may also be helpful for the possible design of contingency plans.
The present working document is an 'alive' document. It should be regularly reviewed and updated as further information becomes available.
II. Camel prion disease1
Camel prion disease (CPrD) was diagnosed in 2018 in three adult camels showing clinical signs at the ante-mortem inspection at an abattoir in the region of Ouargla (Algeria) [1]. According to the published report symptoms suggesting prion disease occurred in 3.1% of dromedaries brought for slaughter to the Ouargla abattoir in 2015–2016. More recently, in 2019, the same disease was reported in the region of Tataouine (Tunisia) [2]. CPrD adds to the group of animal prion diseases,
1 Modified from the OIE Bulletin: https://oiebulletin.com/wp-content/uploads/2019/12/OIE-NewsDecember-2019-Camel-priondisease.pdf?utm_source=World+Organisation+for+Animal+Health+%E2%80%93+OIE+Bulletin&utm_c ampaign=388d499799- EMAIL_CAMPAIGN_2019_12_05_09_06&utm_medium=email&utm_term=0_7694a173d1- 388d499799-54758659
including scrapie in sheep and goats, chronic wasting disease (CWD) in cervids and Bovine spongiform encephalopathy (BSE) in cattle. As of today, very limited epidemiological information is available about the prevalence, geographical distribution and mode of transmission of the disease.
The involvement of lymphoid tissue in prion replication, observed both in the Algerian and Tunisian cases [1,2], is suggestive of a peripheral pathogenesis, which is thought to be a prerequisite for prion shedding into the environment. As with other animal prion diseases, such as scrapie and CWD, in which lymphoid tissues are extensively involved and horizontal transmission occurs efficiently under natural conditions, the detection of prion proteins in lymph nodes is suggestive of the infectious nature of CPrD and concurs to hypothesize the potential impact of CPrD on animal health. No evidence is currently available with which to argue for the relevance of CPrD for human health. However, no absolute species barrier exists in prion diseases and minimizing the exposure of humans to prion-infected animal products is an essential aspect of public health protection.
The worldwide camel population is ~35 million head, 88% of which is found in Africa [4]. The camel farming system is evolving rapidly, and these animals represent vital sources of meat, milk and transportation for millions of people living in the most arid regions of the world. This makes it necessary to assess the risk for animal and human health and to develop evidence-based policies to control and limit the spread of the disease in animals, and to minimize human exposure. As a first step, the awareness of Veterinary Services about CPrD and its diagnostic capacity needs to be improved in all countries where dromedaries are part of the domestic livestock.
Since the first description of CPrD, the OIE promoted discussions on the impact of this new disease through the OIE Scientific Commission for Animal Diseases (Scientific Commission). It evaluated if CPrD should be considered an ‘emerging disease’ based on the criteria listed in the Terrestrial Animal Health Code. The OIE Scientific Commission noted that limited surveillance data were available on the prevalence of CPrD and that the evidence was not enough to measure, at that time, the impact of the disease on animal or public health. Therefore, it was concluded that, with the current knowledge, CPrD did not currently meet the criteria to be considered an emerging disease.
Nonetheless, it was emphasized that CPrD should be considered as a new disease not to be overlooked and called for the collection of further scientific evidence through research and surveillance in the affected countries and in countries with dromedary camel populations to measure the impact of the disease. As new scientific evidence becomes available, the OIE Scientific Commission will reassess whether this disease should be considered as an emerging disease. At the regional level, CPrD was first discussed in the 18th Joint Permanent Committee of the Mediterranean Animal Health Network (REMESA) held in Cairo, Egypt, in June 2019 and at the 15th Conference of the OIE Regional Commission for the Middle East in November. During this conference, the CAMENET launched a wide-ranging proposal for training, coordinated surveillance and research on CPrD. In addition, the ERFAN (Enhancing Research for Africa Network), a platform aimed at enhancing scientific cooperation between Africa and Italy, during its 2nd ERFAN meeting for North Africa, presented a project on CPrD with the objective of increasing CPrD coordinated surveillance in North Africa.
The OIE, through its Reference Laboratories for prion diseases, and by involving the above scientific initiatives, is keeping a close watch on the evolution of the disease to gather scientific evidence and to allow a proper and more thorough assessment of the risk associated with this novel disease.
III. Case definition
Clinical criteria
The clinical manifestations of CPrD cases from Algeria included weight loss, behavioral abnormalities and neurologic symptoms, such as tremors, aggressiveness, hyper excitability, abnormal and excessive movement of the neck and head, hesitant and uncertain gait, ataxia of the hind limbs, occasional falls, and difficulty getting up as the disease progresses.
As of today, in Algeria, CPrD has been reported in animals over 9 years of age [1]. However, two CPrD-affected animals aging 3 years have been recently diagnosed from Tunisia [Agrimi, personal communication].
Therefore, animals of ≥3 years of age, with abnormal behavior and neurological symptoms, in which rabies and other diseases causing neurological symptoms have been ruled out, should be considered as clinically suspects.
Laboratory criteria
Although the vacuolation of neurons and neutrophil (spongiform degeneration) is frequently detected, it is not an obligatory neuropathologic feature of prion disease. The presence of astrogliosis and micro-gliosis, although not specific histologic alteration to the prion diseases, are more constantly seen. The lack of a lymphocytic inflammatory response is also an important characteristic. In the CPrD cases studied to date spongiosis is faint. Therefore, CPrD diagnosis cannot rely purely on histopathology, but PrPSc detection in the brain is crucial for a proper diagnostic assessment [5]. The detection of disease specific PrP (PrPSc) is obtained by means of:
− Western blot
− Immunohistochemistry
In addition to the detection of PrPSc by immunohistochemistry (IHC) and Western blot, the socalled "rapid tests", mainly based on the ELISA technique, have been developed and extensively used in Europe for the surveillance of prion diseases in cattle and small ruminants. Rapid tests are used as screening approaches in active surveillance and usually require confirmation of positive samples by confirmatory Western blot or IHC [5].
Epidemiological criteria
Epidemiological criteria to be considered include: i) reporting in the area of neurological signs in camels for which diagnostic investigations for other diseases causing nervous symptoms were negative or inconclusive; ii) import of camels from areas where CPrD cases have been reported. Case classification It is still early for a formal case classification of CPrD. Nevertheless, a preliminary classification is required for the time being and can be refined gradually as knowledges progress.
1. Possible case: any dromedary of ≥3 years of age with one of the following clinical signs:
a. Behavioral abnormalities including aggressiveness and tendency to kick and bite
b. Nervous signs such as tremors and hyper excitability
c. Abnormal and excessive movement of the neck and head, hesitant and uncertain gait, ataxia of the hind limbs.
d. Downer camels, defined as any animal of ≥3 years of age that is recumbent, lying down on chest or side and unable to get up or stand unassisted. There are many possible reasons for an animal staying down. However, diagnostic investigations for prion diseases in downer cattle represented a crucial step of BSE surveillance in Europe. The relevance of downers animals for CPrD surveillance is not known, but it deserves to be investigated.
2. Probable case: any camel of ≥3 years of age, meeting the clinical criteria and with epidemiological link to a known infected area.
3. Confirmed case: any camel meeting the laboratory criteria for case confirmation, whether it fulfils the clinical criteria or not.
IV. Epidemiological surveillance
Different types of surveillance do exist. Regular reporting of disease cases by competent authorities is called passive surveillance. It involves passive notification by surveillance sites and there is no active search for cases. Active Surveillance occurs when competent authorities proactively look for disease cases.
The type of surveillance for a particular disease depends on the attributes of that disease (e.g. risk for animals and humans) and the objectives of the surveillance.
Until 1999, BSE surveillance in Europe was limited to the notification of clinically suspected cases by farmers and veterinarians to the veterinary authorities (passive surveillance). However, because passive surveillance relies solely on the reporting of clinical suspects and is dependent on many factors, including perceived consequences on the farm and diagnostic competence, it is not necessarily consistent or reliable. In Europe, underreporting has been an important constraint in the passive surveillance of BSE. To optimize the identification of positive animals, improve the surveillance data and increase the consumers' confidence, those populations of cattle that were identified as at increased risk of having BSE were actively targeted within national surveillance systems. In Europe, the population of all healthy slaughtered cattle over 18 months of age were submitted, for several years, to active surveillance by diagnostic rapid tests.
Although active surveillance on healthy slaughtered animals is able to increase the sensitivity of surveillance and to provide a more complete estimate of disease frequency, it is costlier and more labor intensive. In the context of CAMENET Countries, its implementation can be possibly considered, if needed, as a further step.
In the framework of the present program, CPrD surveillance should be targeted to:
1. suspected cases found at farms, pastures or slaughterhouses
2. animals "at risk" of ≥3 years of age, such as:
✓ fallen stock which have died or been killed, not in the framework of an epidemic
✓ emergency slaughtered animals, downer dromedaries.
V. Biosafety
In prion-affected animals, the highest concentration of prions is found in the central nervous system (CNS), therefore caution must be exerted when handling CNS samples. In BSE-affected cattle, more than 90% prion infectivity is found in the CNS, while in scrapie and CWD, prions are spread in the cerebrospinal fluid, spleen/lymph nodes, lung, liver, kidney, placenta, etc. [6]. Preliminary results in CPrD show that, beside the CNS, prions are detected also in lymphoid tissue [1].
Depending on the country, animal prions are classified in the risk class 2 or 3, with scrapie always included in class 2 and BSE in 2/3 or 3 [6,7]. Prions are normally, not transmitted via respiratory route [7].
Risk assessment is required to work with prions and biosafety protocols need to be developed for both laboratory work and sampling activity in the field.
The main risks are wounds from cutting, inoculation or accidental ingestion. Personal protective equipment and ad hoc procedures need to be developed to minimize these risks. Prions are resistant to chemicals and procedures traditionally used for decontaminating classical infectious agents. They are very resistant to chemical and physical agents and are very persistent in contaminated environments [7].
Therefore, working area for prions should be separated from other activities and frequently decontaminated. Cleaning and decontamination procedures of equipment and work surfaces, as well as waste management, take on strategic importance in protecting workers' health and the environment [7].
The absence of a complete and formally certifiable decontamination procedure due to the unavailability of analytical methods capable of detecting traces of the agent in the work environment, makes incineration still the safest method for the elimination of prion-contaminated material. Where possible, therefore, disposable materials should be used, disposed of by incineration. Instruments and other material should be dedicated to prions and left in the prion area
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[7]. As for non-disposable materials, such as laboratory equipment, refrigerators, computers, these should be dedicated and appropriately and necessarily decontaminated through the use of NaOH, NaClO or autoclaving at high temperatures, before being disposed of. Decontamination protocols suggest using solutions of NaOH 2N or NaClO with 20.000 ppm of active chlorine for the decontamination of laboratory surfaces, instruments, etc. Alternatively, heat-resistant materials can be submitted to autoclave with gravity replacement or steam input at 134 ° C for at least 30 min [8] (Table. 1).
Equipment
1. Immerse the equipment in a solution of 1N NaOH (40 g per liter of water) or NaClO with 20,000 ppm of free chlorine for at least one hour; remove the equipment from the solution and put them in gravity replacement or steam injection autoclave at 134 °C for at least 30 min.
2. Immerse the equipment in a solution of 2N NaOH or NaClO with 20,000 ppm of free chlorine for at least one hour. Wash the equipment thoroughly in water. Surfaces (lab benches, hoods, etc.)
Use 2 N NaOH solution (80 grams per liter of water) for at least one hour or, alternatively, NaClO solution with 20,000 ppm of free chlorine for at least one hour. It is always advisable to protect the surfaces with absorbent and waterproof material as a precaution to limit contamination.
Histological preparations
The tissues to be used for histological examination are decontaminated by immersing them in 96% formic acid for 1 h. This precaution reduces the risk of infection resulting from accidents during microtome cutting procedures.
Table 1. Decontamination procedures for instruments (in decreasing order of efficiency), surfaces and samples for histology.
VI. Capacity building
In the present context, capacity building is addressed to build and strengthen organizational and technical capacities for laboratory staff and field veterinarians, in its own role, to recognize CPrD, take part in surveillance activities and carry out laboratory diagnosis. At the same time, personnel from Competent Authorities can acquire basic information and knowledge for the design and implementation of possible contingency plans.
Training is a crucial component of capacity building. It aims at:
- improving the capacity of field Veterinarians to identify CPrD suspect cases
- building and strengthening the capacity of laboratory diagnosis of CPrD
- providing National Veterinary Services basic knowledge for risk analysis, early warning and contingency plans development
- providing practical experience on laboratory methods for the diagnosis and investigation of CPrD
Training programs can be done in-country or in a reference laboratory such as ISS and/or IZSPLVD. Training consists of two components:
Training programmes will include:
1) Courses for field veterinarians, laboratory staff and veterinary services personnel
a) Prion diseases of humans and animals
- Basic concepts on prions and prion diseases of humans and animals: nature of the causative agents, pathogenesis, risk for humans and animals
- Epidemiology and surveillance of animal prion diseases
- Diagnosis of animal prion diseases
- Biosafety guidelines to protect both the personnel and the environment (biocontainment)
b) Camel Prion Disease
- Clinical diagnosis of CPrD and recognition of suspected cases
- Surveillance
- Sampling at post-mortem in slaughterhouses, incinerator facility, farm or other collection site, storage and transport to the lab
- Data collection by using standardized forms
- Audiovisual aids for CPrD
- Communication protocols
2) Courses for laboratory staff
- Laboratory methods and techniques for CPrD diagnosis and research (OIE-approved methods, rapid tests and others)
- Characterization of prion strains: laboratory techniques and interpretation of results
- Analysis of the PrP gene (PRNP)* [1,9]
- Laboratory equipment
- Biosafety and biocontainment procedures under laboratory conditions
VII. Early warning and response
Due to its geographical location, the Middle East is under risk of transboundary animal diseases from Africa and Asia. No information is available on CPrD in the region but the presence of camels and their import from neighboring countries suggest extending the knowledge on CPrD spread also in this geographic area.
Based on the current limited knowledge, CPrD does not meet the OIE criteria to be considered an emerging disease. However, the suspect of its transmissibility under field conditions makes emergency preparedness and contingency planning important tools for its control, in case CPrD is found.
In the present context, only the basic principles of early warning and response planning for CPrD are provided.
Emergency preparedness planning for emergency diseases introduction is comprised of two main components: 1) early warning and 2) early response [10].
* Sequence analyses in prion diseases cannot be applied for diagnosis since prions are devoid of nucleic acid. However, PrP sequence analysis is important because in sheep, goat and deer, PRNP polymorphisms have a strong influence on prion susceptibility/resistance.
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1. Early warning.
It includes all actions (disease surveillance, reporting and epidemiological analysis) aimed at the rapid detection and assessment of the introduction of the disease. In particular, an effective early warning system should comprise:
- updated diagnostic capacities
- effective surveillance systems
- access to and analysis of real-time data
- efficient epidemiological support
- efficient and multidirectional reporting systems
- suitable and efficient organization of the various components of the system
2. Early response.
It comprises the effective and rapid implementation of all measures needed to contain the outbreak and to eliminate it progressively. This goal is achieved through the development of national contingency plans. These include:
- national coordination - Strategical operation plan with an effective control center, well identified key roles and efficient/effective communication
- risk assessment - assessing the risk associated with importation and spread of the disease
- efficient access to and analysis of continuously updated data
- communicating with veterinary and food sector services as well as with public health sector (if public health issues arise)
- when capacity building is not available at national level, a regional capacity-sharing system should be established
- animal health management and public health management (if needed) - Involvement and participation of all stakeholders, including breeders’ associations. Information and education are crucial
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- public information and the media - Providing a transparent information and establishing a strong emergency response system is key in improving the confidence and reassurance of public
- rapid and efficient communicating with OIE and international organizations also for possible foreign technical and economic support.
VIII. Risk Factors
Prion diseases present in animals with different origins:
- as putatively spontaneous diseases, such as atypical/Nor98 scrapie of sheep and goats and in atypical BSE (in its L-type and H-type forms)
- as infectious, but not contagious diseases, such as classical BSE, where the disease is only transmitted via infected feedstuff and cattle behave as dead-end hosts being not able to transmit the disease to healthy animals
- as infectious and contagious disease, such as scrapie or CWD, where the disease spreads from infected to healthy animals in the flock.
Our limited knowledge on CPrD prevents to definitely classify this new disease into the previous categories. However, the involvement of lymphoid tissue observed in the first cases is suggestive of the infectious and contagious nature of the disease.
No information is available about possible relationship between CPrD and other animal prion diseases. Although the origin of CPrD from another prion disease cannot be ruled out, as of today, the presence of other prion diseases is not considered a risk factor for CPrD.
No information is available about the distribution of infectivity in tissues of CPrD-affected animals. Although the detection of PrPSc in the nervous system and lymphoid tissue is reminiscent of what is usually seen in sheep scrapie, no conclusion can be drown at this stage about the risk of CPrD-affected animals.
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Given the limitless of current knowledge, the following list of risk factors for CPrD should be only regarded as indicative and needed to be updated and refined as knowledges progress.
1. Potential import risk factors
a. Import of dromedaries from infected areas.
b. Incursion of free-ranging infected dromedaries through permeable country borders.
c. Import of dromedaries’ products, included meat and bone meal produced with dromedaries' offals, from infected areas.
d. Potential incursion of disease by importation of contaminated camels feed with meat and bone meal produced with dromedaries' offals.
2. Potential risk factors within the country
e. Presence of camels (susceptible animals).
f. Absence of an effective surveillance system for prion diseases
g. Type of production system:
✓ extensive breeding systems with different dromedary herds sharing common pastures and limited effectiveness of surveillance
✓ nomadic movements of animals along distances with limited effectiveness of surveillance
✓ intensive breeding system with the use of processed camel proteins in feedstuff
h. Processing of camel's offal for the production of animal by products
i. Absence of animal identification and traceability systems.
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Potential risk factors for humans
To date, no information is available on the risk of CPrD for humans.
Given the limited knowledge of the molecular basis of the "barrier" existing in the transmission of prion diseases between different species, measures have been adopted in Europe to minimize the exposure of humans to any prion diseases.
Therefore, the consumption of central nervous system and lymphoid tissue from CPrD-infected camels should be avoided as precautionary measure.
IX. Knowledge gaps
Multiple areas of understanding and knowledge of CPrD need to be investigated to fill the many existing gaps. Among the others:
- Origin of CPrD - Is CPrD a newly emerged disease or it is a long existing but unrecognized disease of dromedaries?
- Geographic distribution of CPrD.
- CPrD strain characterization - Does CPrD have any relationship with other animal prion diseases? Similarities and differences with other animal prion strains.
- Is CPrD sporadic or infectious? This is of relevance for animal health and strongly affects the control measures.
- Pathogenesis and prion/infectivity distribution in dromedary tissues - This is of relevance for animal and human risk.
- Risk for other camelids and other animal species
- Risk for humans
- CPrD epidemiology and risk factors
- Others
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X. References
1. Babelhadj B, Di Bari MA, Pirisinu L, Chiappini B, Gaouar SBS, Riccardi G, Marcon S, Agrimi U, Nonno R, Vaccari G. Prion Disease in Dromedary Camels, Algeria. Emerging Infectious Diseases. Vol. 24, No. 6, June 2018
2. OIE Representation in Africa - News: "June 2019 - 18th meeting of the REMESA Joint Permanent Committee in Egypt (Cairo) [abridged, edited] http://www.rrafrica.oie.int/en/news/20190627.html
3. World Organization for Animal Health. OIE Bulletin, December, 2019. https://oiebulletin.com/wp-content/uploads/2019/12/OIE-News-December-2019-Camelpriondisease.pdf?utm_source=World+Organisation+for+Animal+Health+%E2%80%93+OIE+Bu lletin&utm_campaign=388d499799- EMAIL_CAMPAIGN_2019_12_05_09_06&utm_medium=email&utm_term=0_7694a173d 1-388d499799-54758659
4. Food and Agriculture Organization of the United Nations. Live animals [cited 2017 Nov 10]. http://www.fao.org/faostat/en/#data/QA
5. Bovine Spongiform encephalopathy, Chapter 3.4.5, OIE Manual of Diagnostic Tests and Vaccines for Terrestrial Animals. Updated 2016
6. World Health Organization (2010). Tables on Tissue Infectivity Distribution in Transmissible Spongiform Encephalopathies. WHO/EMP/QSM/2010.
7. Health and Safety Executive (HSE) Advisory Committee on Dangerous Pathogens. The Approved List of Biological Agents. 2013 Edition available via http://www.hse.gov.uk/pubns/misc208.pdf
8. Leunda A, Van Vaerenbergh B, Baldo A, Roels S, Herman P (2013) Laboratory activities involving transmissible spongiform encephalopathy causing agents. Risk assessment and biosafety recommendations in Belgium. Prion 7:5, 420–433.
9. Kaluz S, Kaluzova M, Flint AP. Sequencing analysis of prion genes from red deer and camel. Gene. 1997; 199:283–6.
10. Sinan Aktas. Emergency preparedness: formulation and implementation of animal health contingency plans in the Middle East. World Organization for Animal Health. https://www.oie.int/doc/ged/D2963.PDF
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List of contributors: ADAFSA, UAE ISS, Italy IZSPLVA, Italy Salama Almuhairi Abdelamlik Khalafalla Mohamed Alhosani Oum Kalthoum Bensalah Hassan Zakaria Umberto Agrimi Gabriele Vaccari Michele Di Bari Romolo Nonno Laura Pirisinu Barbara Chiappini Ilaria Vanni Claudia D'Agostino Cristina Casalone Giuseppe Ru
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''Since the first description of CPrD, the OIE promoted discussions on the impact of this new disease through the OIE Scientific Commission for Animal Diseases (Scientific Commission). It evaluated if CPrD should be considered an ‘emerging disease’ based on the criteria listed in the Terrestrial Animal Health Code. The OIE Scientific Commission noted that limited surveillance data were available on the prevalence of CPrD and that the evidence was not enough to measure, at that time, the impact of the disease on animal or public health. Therefore, it was concluded that, with the current knowledge, CPrD did not currently meet the criteria to be considered an emerging disease.''
***> SEEMS TO ME that the OIE et al likes to wait until a terrible animal disease is well established, spread around the world, and at the brink of being discovered and documented as a zoonosis disease before considering it a zoonosis zoonotic disease, before considering it a emerging disease. damn shame, and we will address that at the bottom of this report..terry
Monday, September 14, 2020
Assessing the aggregated probability of entry of a novel prion disease agent into the United Kingdom
■ The prevalence of CPD in camels in the region of interest - 3.1% (based on Babelhadj et al. (2018))
■ The incidence and prevalence of CPD in camel products, derived from:
Tuesday, April 27, 2021
Working Document on Camel Prion Disease (CPrD) 14/09/2020
Video of Camel with Suspected CPD
JOURNAL ARTICLEOPEN ACCESS
Prion disease in dromedary camels, Algeria
Babelhadj BDi Bari MPirisinu L et al.
Emerging Infectious Diseases (2018) 24(6) 1029-1036
DOI: 10.3201/eid2406.172007
Prions cause fatal and transmissible neurodegenerative diseases, including Creutzfeldt-Jakob disease in humans, scrapie in small ruminants, and bovine spongiform encephalopathy (BSE). After the BSE epidemic, and the associated human infections, began in 1996 in the United Kingdom, general concerns have been raised about animal prions. We detected a prion disease in dromedary camels (Camelus dromedarius) in Algeria. Symptoms suggesting prion disease occurred in 3.1% of dromedaries brought for slaughter to the Ouargla abattoir in 2015–2016. We confirmed diagnosis by detecting pathognomonic neurodegeneration and disease-specific prion protein (PrP Sc ) in brain tissues from 3 symptomatic animals. Prion detection in lymphoid tissues is suggestive of the infectious nature of the disease. PrP Sc biochemical characterization showed differences with BSE and scrapie. Our identification of this prion disease in a geographically widespread livestock species requires urgent enforcement of surveillance and assessment of the potential risks to human and animal health.
THURSDAY, NOVEMBER 10, 2022
Annual Report of the Scientific Network on BSE‐TSE 2022
https://efsaopinionbseanimalprotein.blogspot.com/2022/11/annual-report-of-scientific-network-on.html
SUNDAY, OCTOBER 16, 2022
USDA Transmissible Spongiform Encephalopathy TSE Prion Action Plan National Program 103 Animal Health 2022-2027
MONDAY, SEPTEMBER 19, 2022
589.2001 BSE TSE regulations which prohibits the use of high-risk cattle material in feed for all animal species 2022
SUNDAY, OCTOBER 30, 2022 Why is USDA "only" testing 25,000 samples a year?
https://bovineprp.blogspot.com/2022/10/why-is-usda-only-testing-25000-samples.htmlTUESDAY, APRIL 05, 2022
2022 American Academy of Neurology Emerging Sciences Abstract Website Incidence of Creutzfeldt-Jakob Disease in the United States 1993-2014
Terry S. Singeltary Sr.
