[Human and animal health]. / Santé humaine et santé animale.

The concept of "one health" applies perfectly to human health and animal health because many diseases are zoonoses. There are many historical examples of effective collaboration between veterinary medicine and human medicine in the development of the first vaccines used in the world (smallpox, rabies, tetanus, diphtheria, tuberculosis, etc.). But when a new disease appears in animals, the risk of possible transmission to humans is difficult to estimate. In the latter case, the loss of consumer confidence in the face of scientific uncertainties can cause a health crisis (examples of bovine spongiform encephalopathy and H5N1 avian plague). But the most serious crisis that we have known since early 2020 is Covid-19 pandemic, which confirms that the modification of the ecosystems of certain wild species such as the horseshoe bats can have significant consequences for the public health. Animals infected with Covid-19 have been contaminated by humans but we cannot currently exclude an animal reservoir risk for SARS-CoV-2 which has circulated around the world.

[Covid-19 and the animal world, from a still mysterious origin towards an always unpredictable future]. / Rapport 21-11. Covid-19 et monde animal, d'une origine encore mystérieuse vers un futur toujours incertain.

Although the emergence of Covid-19 in China has not been clearly elucidated, the hypothesis of an animal origin remains the most likely. It is supported by the presence of the horseshoe bat suspected to be the progenitor of SARS-CoV-2 and by the scarcity of pork, due to African swine fever, diverting consumers to exotic animals of breeding sold in the markets. During this pandemic, several animal species were affected by SARS-CoV-2. Sporadic cases were first reported in pets (dogs and cats) infected by their owners, then in large feline species and apes infected in zoos by their nurses. The most significant human-to-animal transmission has occurred in mink farms, especially in the Netherlands and Denmark, requiring the euthanasia of several million animals, with mink in turn having contaminated men and stray or nomadic cats. The study of natural or experimental transmissions of SARS-CoV-2 has made it possible to identify the most receptive animal species: American minks and raccoon dogs, and to a lesser extent stray or nomadic cats, which could become an animal reservoir due to their sensitivity to this virus and their extending prolificacy. The European Commission decided on May 17, 2021 to strengthen the surveillance of SARS-CoV-2 infections in minks and other mustelids, as well as in raccoon dogs, highlighting stressing that the epidemiological assessment of the risk presented by the he appearance of SARS-CoV-2 in these susceptible species was a public health priority.

[General introduction to animal and human coronaviruses]. / Introduction générale sur les coronavirus animaux et humains.

Coronaviruses are RNA viruses classified into Alphacoronavirus, Betacoronavirus, Gammacoronavirus and Deltacoronavirus. Their name comes from their conformation with the observation of spicules forming a sort of crown. Coronaviruses seem to come from bats, and more particularly Alphacoronaviruses and Betacoronaviruses (the genus where zoonoses are observed), while birds are the source of Gammacoronaviruses and Deltacoronaviruses. The first coronavirus identified was that of avian infectious bronchitis in 1931 in the United States, while the first coronaviruses were described in humans only in the 1960s. This is why coronaviruses were mainly known in the veterinary community. Most Alphacoronaviruses are species specific. They can be responsible for serious diseases such as the cat coronavirus, responsible for feline infectious peritonitis, transmissible gastroenteritis (GET) in piglets and porcine epidemic diarrhea (PED), porcine respiratory coronavirus (PRCV). Finally, a deltacoronavirus can be found in both pigs (PD CoV UKU15) and birds.

Alpha-synuclein accumulates in the brain of scrapie-affected sheep and goats.

Immunohistochemical examination demonstrated widespread granular deposits of alpha-synuclein (alphaSN) in the brains of sheep and goats with natural scrapie, especially in the cornu ammonis and subiculum of the hippocampus; this contrasted with the diffuse and non-granular immunolabelling seen in healthy controls. There was non-regular "co-localization" of PrP(Sc) and alphaSN. The findings resembled those reported in Creutzfeldt-Jakob disease and in experimental prion disease in hamsters and mice. The results suggest that perturbation of alphaSN metabolism plays a role in human and animal prion diseases.

Renal Cryptosporidiosis (Cryptosporidium baileyi) in specific-pathogen-free chickens experimentally coinfected with Marek's disease virus.

Renal Cryptosporidiosis was experimentally induced during a study to investigate the pathogenicity of Cryptosporidium baileyi in specific-pathogen-free (SPF) chickens coinfected with Marek's disease virus (MDV). Cryptosporidium baileyi was administered orally at 4 days of age to chickens previously infected at hatching (day 0) with the HPRS 16 strain of oncogenic MDV. Three control groups received MDV at hatching, C. baileyi on day 4, or placebo consisting of distilled water. Renal cryptosporidiosis lesions were induced in the group coinfected with MDV and C. baileyi. The kidneys were markedly swollen and pale, with visible urate crystals in the ureters and surface tubules. Oocysts of C. baileyi were demonstrated in six of seven cases tested by a scoring method with modified Sheather's sugar solution on renal tissue scrapings and were confirmed in three cases by histologic examination of paraffin-embedded kidney sections. Histologic study also revealed subacute interstitial nephritis, acute ureteritis, and attachment of cryptosporidia on the epithelial cell surface of the ureters and collecting ducts, collecting tubules, and distal convoluted tubules. Various developmental stages of the parasite were present in the kidney sections. To our knowledge, this is the first report of experimentally induced renal cryptosporidiosis in SPF chickens coinfected with MDV.

Urodynamic parameters in scrapie-affected ewes and their modifications in the course of the disease.

The aim of this study was to determine the urological abnormalities linked to spontaneous spongiform encephalopathy and their occurrence in the course of the disease. The animals used in this were 11 healthy and 20 scrapie-affected ewes. The scrapie-affected ewes were studied at a rate of once a month (1 to 5 measures; mean, 2.55) until they died. Urodynamic explorations were performed. The bladder activity was explored using cystometry. The urethral activity was measured during cystometry and during a urethral pressure profile. Both were analyzed using International Continence Society recommendations. Results showed in scrapie-affected ewes a decrease in functional bladder capacity and an increase in detrusor contraction incidence during filling of the bladder and in the occurrence of significant urethral instability. Bladder abnormalities were seen only in scrapie-affected ewes and worsened during the course of the disease. Urethral instability was not typical of the disease but was significantly more frequent in scrapie-affected ewes. It was concluded that lower urinary tract dysfunction occurred in scrapie-affected ewes and worsened during the course of the disease. This dysfunction is in agreement with overactive detrusor function due to neurological lesions.

[Crohn disease: uncertainty about the etiologic role of Mycobacterium paratuberculosis]. / Maladie de Crohn: incertitudes sur le rôle étiologique de Mycobacterium paratuberculosis.

In recent years, attention and discussion have been devoted to the possible association of Mycobacterium paratuberculosis, agent of paratuberculosis in ruminants, with Crohn's disease. Both diseases, which affect young adults, are characterized by chronic granulomatous lesions, typically concentrated in the terminal ileum, and clinical signs of enteritis and weight loss. The etiology of Crohn's disease is unknown but genetic, environmental, immunological and microbiological influences, in various combinations, have been suggested. Human exposure to M. paratuberculosis may occur essentially from a fecal contamination (drinking water, milk...). This association between Crohn's disease and paratuberculosis has been shown but a causal relationship remains to be demonstrated.

[Human and animal spongiform encephalopathy. Update on December 17, 1996]. / Encéphalopathies spongiformes humaines et animales. Actualités au 17 décembre 1996.

Recent papers about bovine spongiform encephalopathy (BSE) and new variant of Creutzfeldt-Jakob disease (nvCJD) are reviewed: new data, maternal transmission of BSE, epidemiology of BSE in British cattle, structure of the PrP(res), biochemical signature of PrP(res), chronic pesticide-initiated modification of the prion protein, protein markers in cerebrospinal fluid.

[Bovine spongiform encephalopathy. Second update of data collected since the report of February 6, 1996]. / Encéphalopathie spongiforme bovine. Deuxième mise au point des données recueillies depuis le voeu du 6 février 1996.

The observation in 1995 and 1996 of 12 cases of a new variant of Creutzfeldt-Jakob disease (V-CJD) in U.K. suggested a possible relation between this human cases and bovine spongiform encephalopathy (BSE). Recent papers about this topic are reviewed: BSE transmission to macaques, transmission of scrapie with embryo transfer, incidence of maternal transmission, PrP protein released by platelets, diagnostic test by detection of PrP protein in tissues of sheep, epidemiology of BSE, french regulations, identification of cattle in U.K.

[Bovine spongiform encephalopathy. Review of data collected since the statement of February 6, 1996]. / Encéphalopathie spongiforme bovine. Mise au point des données recueillies depuis le voeu du 6 février 1996.

The observation in 1995 and 1996 of 10 cases of a new variant of Creutzfeldt-Jakob disease (V-CJD) in U.K. suggested a possible relation between this human cases and bovine spongiform encephalopathy (BSE). Recent papers about this topic are reviewed : hypothesis of a possible genetic link between man and cattle, hypothesis of a acquired resistance against the agent of BSE after a previous infection by a less virulent agent of ovine origin, importance of polymorphism at codon 129 according to the hypothesis of a virus-induced amyloidosis, diagnostic test with cerebrospinal fluid, epidemiology of BSE and prediction of future BSE spread.

[Bovine spongiform encephalopathy and Creutzfeldt-Jakob disease. Current questions]. / Encéphalopathie spongiforme bovine et maladie de Creutzfeldt-Jakob. Actualités.

The occurrence of Creutzfeldt-Jakob disease (CJD) in two teenagers and four dairy farmers in the United-Kingdom has focused attention on the possibility of a causal link between bovine spongiform encephalopathy (BSE) and Creutzfeldt-Jakob disease. The BSE epidemic was initiated by the inclusion in the cattle feed of the ruminant-derived protein in 1981/1982. A feed ban of the ruminant-derived protein in 1988 prevented further transmission of the infective agent to cattle by this route. However cases in animals born some years after the feed ban suggest that there has been some continued leakage of BSE infected material into animal feed (and perhaps maternal transmission?). To protect public and animal health, measures have been taken in the United Kingdom, especially prohibition of specified bovine offals in 1989 (extending this ban to thymus and intestine of calves slaughtered for human consumption in 1994). These measures are considered as minimizing the risk of BSE infection. Although the BSE linked risk factors are probably unique to the United Kingdom, it seems necessary to have the same regulations for the calves imported from this country. More, it is crucial that the ongoing surveillance programme of CJD in Europe is sustained.

[Scrapie in sheep and transmissible encephalopathy of the mink]. / La tremblante du mouton et l'encéphalopathie transmissible du vison.

Scrapie in sheep and goat is the prototype of the group of the transmissible spongiform encephalopathies which affect man and some animal species, notably other ruminants with bovine spongiform encephalopathy (BSE) and chronic wasting disease of wild ruminants. Transmissible mink encephalopathy (TME) is a rare disease of ranch-raised mink caused by exposure to a contaminated food ingredient in the ration scrapie, unrecognised BSE-like disease...). There is clinical and pathological similarities between TME and scrapie. These diseases share the following characteristics: a prolonged incubation period; a progressive, debilitating, neurological illness (always fatal); pathological changes confined to the central nervous system (vacuolisation, neurological loss, astrocytosis); the presence of scrapie-associated-fibrils (SAF) in brain tissue; and absence of detectable inflammatory or immune responses. The genetic origin of scrapie in sheep and the natural transmission of these spongiform encephalopathies are discussed.

Astroglial reactivity in natural scrapie of sheep.

Astrogliosis is known to be a common histological feature in experimental scrapie, but astroglial reactivity in natural scrapie of sheep has not yet been precisely studied. We investigated the expression of two markers of glial plasticity, glial fibrillary acidic protein (GFAP) and glutamine synthetase (GS), by Western and Northern blotting, in different areas of the sheep brain. We report that both GFAP-mRNA and GFAP are overexpressed in the cerebellum and the pons. In the thalamus, overexpression of GS was demonstrated for the first time in this disease. The enhancement of this astroglial metabolic marker, essential for glutamate and ammonia neutralization, cellular function and brain detoxification, could represent an attempt by astrocytes to maintain and control the cerebral homeostasis in this area. Our results show that astrocytes: (i) are a target for the scrapie agent even in the early temporal evolution of the disease; (ii) react by overexpressing their intermediate filament major protein, changing their phenotypic appearance and stabilizing their processes in precise brain areas; (iii) overexpress key elements of their metabolism. These changes clearly implicate astrocytes in the pathogenesis of the disease.

[Transmissible animal spongiform encephalopathies]. / Les encéphalopathies spongiformes transmissibles animales.

Scrapie in sheep and goats was the first animal spongiform encephalopathy diagnosed. It has since been described in a large number of species (cattle, wild and exotic ruminants, mink, cat). They form an original group of diseases because they are transmissible by a specific pathogen and they depend on the genetic predisposition of the recipient animal. Transmission between species and the possibility of oral transmission underline the need to assess the risk to Man.

[Transmissible animal spongiform encephalopathies. Epidemiologic aspects]. / Les encéphalopathies spongiformes transmissibles animales. Aspects épidémiologiques.

This article presents an update of data about the transmissible spongiform encephalopathies which affect some animal species, particularly bovine spongiform encephalopathy in Great britain and in other countries where this disease is sporadic. The genetic susceptibility of scrapie in sheep and the natural transmission of these spongiform encephalopathies are discussed. The control measures for public health and animal health are presented.

PrP polymorphisms associated with natural scrapie discovered by denaturing gradient gel electrophoresis.

Scrapie is a transmissible degenerative disease of the central nervous system occurring naturally in sheep and goats. An abnormal protease-resistant form of the host-encoded prion protein (PrP) accumulates in the brains of affected animals. As Sip, a gene controlling the incubation period of experimental and natural scrapie, is linked to the single-copy sheep PrP gene, we sought PrP coding sequence polymorphisms in flocks from the Romanov and Ile-de-France breeds endemically affected with natural scrapie. DNA samples from 153 sheep, including 29 natural scrapie cases, were screened by using polymerase chain reactions and denaturing gradient gel electrophoresis. Four predicted amino acid substitutions were found in the center of the PrP coding region: 112 Met-->Thr, 136 Ala-->Val, 154 Arg-->His, and 171 Gln-->Arg. These substitutions appeared mutually exclusive, defining five coding alleles. The 136Val allele, substituting a highly conserved Ala residue, in a homozygous or heterozygous state correlated with susceptibility to natural scrapie (chi 2 = 64.33, P < 0.001). This correlation indicates that the 136 Val allele may modulate development of the disease, implying a pivotal role for PrP molecules in natural scrapie, as has been observed for experimental scrapie and human prion diseases.

[Bovine spongiform encephalopathy: a new entity caused by a non-conventional transmissible agent]. / L'encéphalopathie spongiforme bovine: une nouvelle entité provoquée par un agent transmissible non conventionnel.

In 1986, a new neurologic disease appeared in the Great Britain's Cattle. According to its histological lesions, this condition belongs to the group of transmissible encephalopathies known as spongiforme encephalopathies (SE). These SE are associated with no-conventional transmission agent (NCTA) or Prion. At the time of writing, over 13,000 cases of Bovine spongiforme encephalopathy (BSE) have occurred in UK. The most likely origin of this dramatic outbreak would be an oral contamination of Cattle by the feeding of sheep carcasses or of all infected with scrapie, another SE, incorporated to concentrates. Possible factors as changes (lower temperatures and reduced use of organic solvents to extract fats) in the rendering process could have preserved the very resistant Prion in these concentrates. The important lessons resulting from our present knowledge and hypothesis are there would be no species barrier to impede transmission of the NCTA through oral route. The question concerns the public health risks posed by BSE. Two related diseases of human are Kuru and Creutzfeldt-Jacob disease. At the present time, based upon epidemiological datas on scrapie, BSE is unlikely to be a major threat to humans. Nevertheless, precautionary steps to reduce a potential risk to an absolute minimum were taken by British regulations and more recently, by European directives.