Systematic review of the prevalence of paratuberculosis in cattle,sheep, and goats in Latin America and the Caribbean

Mycobacterium avium subsp. paratuberculosis causes paratuberculosis or Johne’s disease (JD) in domestic ruminants and wild species. The aim of the present study was to systematically review the prevalence of paratuberculosis among farmed animals (cattle, sheep, and goats) in Latin America and the Caribbean. The initial search for existing publications reporting systematic reviews and primary studies was carried out by searching the available databases. For the final selection of studies, an initial screen for basic eligibility and a detailed appraisal of quality were performed. After study selection, the relevant data were extracted. The detailed appraisal generated 24 publications that reported 52 studies, of which 73.1, 11.5, and 15.4 % were from cattle, sheep, and goats, respectively. Thirty-three (63.5 %) of the studies were animal level studies, while 19 (36.5 %) were herd-/flock-level studies. No flock-level studies on prevalence in sheep were found. Studies in Latin American and Caribbean countries revealed an overall prevalence of 16.9 (95 % CI (confidence interval) 13.2–20.5) and 75.8 % (95 % CI 50.1–101.5) in cattle at the animal and herd levels, respectively; the prevalence was 16 % (95 % CI 7.9–24.1) in sheep at the animal level and 4.3 % (95 % CI 1.9–6.8) and 3.7 % (95 % CI 0.1–7.4) in goats at the animal and flock levels, respectively. In general, prevalence results reported by the studies were insufficient to accurately determine the prevalence of paratuberculosis in farmed animals in Latin America and the Caribbean. Several flaws in the design of studies limit the quality of evidence regarding the prevalence of paratuberculosis in the region.     

Filarioid nematodes in cattle,sheep and horses in Finland

Background

In autumn 2006, Finnish meat inspection data revealed lesions in tendons, muscles and ligaments of bovine hind legs leading to partial condemnation of carcasses. In gross pathological examination at Finnish Food Safety Authority Evira, Oulu (now Fish and Wildlife Health) Research Unit, Onchocerca sp. (Filarioidea; Onchocercidae) nematodes were detected in lesions. Due to this, a pilot study was made in order to find out what filarioid nematodes do occur in cattle, horses and sheep in Finland.

Methods

Ventral skin biopsies from 209 dairy cattle and 42 horses, as well as blood samples from 209 cattle, 146 horses and 193 sheep, were collected from different parts of Finland and examined for microfilariae. Visceral organs and other tissues from 33 cattle with parasitic lesions were studied histopathologically.

Results

Onchocerca sp. microfilariae (mf), 240 μm long, range 225–260 μm, 5.4 μm thick, were found in 37% of the skin biopsies of cattle. All blood samples from cattle, horses and sheep and skin biopsies from horses were negative for mf. Ventral skin microfilaria prevalence in cattle was higher in southern Finland than in the North (p = 0.001). Animal age and sampling time was not associated with mf prevalence. The infection was evenly distributed among young and older animals. Macroscopic lesions on tissues included greenish-grey discolouration and often oedema. In most of the lesions, small pale nodules were seen on the fasciae. Histopathologic examination of the samples revealed mild to intense infiltration with eosinophilic granulocytes and multifocal nodular lymphoplasmacytic aggregations were seen. In some samples, there were granulomatotic lesions with central necrotic tissue and cell detritus, surrounded by eosinophilic granulocytes, lympho-, plasma- and histiocytes and some multinucleated giant cells. Around living nematodes no or only weak inflammatory changes were observed.

Conclusion

Onchocerca sp. infection in cattle was found to be common in Finland, but the amount of pathological changes leading to condemnation of infected parts is low compared to the mf prevalence. Pronounced pathological changes are distinct but rare and mild changes are difficult to distinguish. No other filarioid nematodes were observed from the animals and it appears that horses and sheep may be free from filarioid nematodes in Finland.     

Lysozyme concentrations in the tears of cattle, goats, and sheep

Tear samples were collected from 1 eye of each of 40 cows, 27 sheep, 5 goats, and 5 human beings. Additionally, 10 bovine tear samples were pooled and concentrated. Spectrophotometric assays, using Micrococcus lysodeikticus, were performed on each sample to detect lysozyme activity expressed in hen egg lysozyme (HEL) equivalents. Lysozyme activity was not detected in tears of cows, but 158.8 +/- 159.3 mg of HEL/ml was detected in tears of sheep, 220.7 +/- 37.5 mg of HEL/ml in tears of goats, and 216.3 +/- 86.2 mg of HEL/ml in tears of human beings. In pooled bovine tear samples, lysozyme activity was not detected on plate assay and lysozyme protein was not detected on polyacrylamide gel electrophoresis, column chromatography, or immunoelectrophoresis with rabbit anti-bovine tear antibodies. On the basis of these observations, we concluded that the basic ocular protective mechanism in bovine tears is not lysozyme. Other anti-bacterial proteins such as lactoferrin, transferrin, complement, or beta-lysin may, therefore, be of primary importance in protecting the bovine eye.     

Lung sounds in cattle, horses, sheep and goats

The purpose of this paper is to emphasize the importance of pulmonary auscultation for the clinician. It suggests a clarification and simplification of the terminology to be used which would be helpful to veterinary students and allow better communications between veterinarians. The interpretation of these sounds and the relationships to conditions and diseases of the lungs in cattle, horses, sheep and goats are discussed.     

Comparison of pepsinogen forms in cattle, sheep and goats

Different types and subtypes of pepsinogen extracted from bovine, ovine and caprine abomasa were found to differ according to their phosphate content and relative molecular mass (Mr). Bovine pepsinogens had organic phosphate contents ranging from 1.65 to 2.22 mol of phosphate mol-1 of pepsinogen. Ovine pepsinogens were in the range 1.50 to 2.36 and caprine pepsinogens were in the range 1.42 to 2.00. The major types of pepsinogen from each species were different in size. Bovine pepsinogen had an Mr of 39,000, ovine had an Mr of 43,000 and caprine pepsinogen had an Mr of 42,000.     

Dynamics of digestion in cattle, sheep, goats and deer

Four experiments were conducted to study factors affecting digestibility of forages in cattle, sheep, goats and white-tailed deer. In a series of digestion trials (Exp. 1), the dry matter digestibility of a moderately high fiber diet was greater in cattle than in deer. Digestibilities of the diet in sheep and goats were intermediate and not different from either extreme. In a second series of trials (Exp. 2), relative organic matter digestibilities were for goats more than sheep more than deer. However, in Exp. 2, intake in goats was very low and digestibility appeared to be positively related to retention time and inversely related to turnover rate. Results of three trials (Exp. 3) suggested that rate of digestion was related more to diet than to the animal species consuming the diet. In grazing animals (Exp. 4), goats digested a smaller percentage of consumed material than either cows or sheep during three of four seasons even though diets were of similar in vitro digestibility. This difference was related to a faster turnover and shorter retention time in goats. These data support the concept that there are species differences in gastrointestinal dynamics which may be which may be important determinants of adaptability to grazing conditions.     

Epidemiology of gastrointestinal nematodes of sheep and goats in Haryana, India

Epidemiological studies on some gastrointestinal nematodes of sheep and goats in Karnal, Ambala and Rohtak districts of Haryana (India) revealed that Haemonchus contortus and Trichostrongylus spp. were responsible for parasitic gastroenteritis in these hosts. The adult parasites persisted in the host throughout the year and there was no indication of hypobiosis. The maintenance of the parasite population depended on a continuous cycle of infection between the host and the pasture. The agroclimatic conditions of the districts revealed that, in general, favourable weather conditions for the development and survival of the free-living stages of the parasites existed all year round.     

Toxoplasmosis in sheep,goats and cattle in central Ethiopia

In a seroepidemiological survey using an indirect haemagglutination assay, the prevalence rate of toxoplasmosis in central Ethiopia was 22.9% of 899 sheep, 11.6% of 753 goats and 6.6% of 785 cattle. There were high titres of 1:256 or more which suggest current infections. These results indicate that toxoplasmosis may be an important cause of reproductive wastage in small ruminants. The public health significance of this disease is discussed. Improved hygiene and management could reduce the prevalence of the disease.     

Cloning and comparison of bighorn sheep CD18 with that of domestic sheep, goats, cattle, humans and mice

Previously, we have shown that CD18, the beta-subunit of beta(2)-integrins, serves as a receptor for leukotoxin (Lkt) secreted by Mannheimia (Pasteurella) haemolytica on bovine leukocytes. Anti-CD18 monoclonal antibodies (mAbs) inhibit Lkt-induced cytolysis of bighorn sheep (Ovis canadensis) leukocytes suggesting that CD18 may serve as a receptor for Lkt on the leukocytes of this species as well. Confirmation of bighorn sheep CD18 as a receptor for Lkt, and elucidation of the enhanced Lkt-susceptibility of bighorn sheep polymorphonuclear leukocytes (PMNs), necessitates the cloning and sequencing of cDNA encoding bighorn sheep CD18. Hence, in this study we cloned and sequenced the cDNA encoding CD18 of bighorn sheep, and compared with that of other animal species. The cDNA of bighorn sheep CD18 has an open reading frame (ORF) of 2310bp. CD18 sequences obtained individually from peripheral blood mononuclear cells (PBMCs) and PMNs were identical to each other. Comparison of the deduced 770-amino acid sequence of CD18 of bighorn sheep with that of domestic sheep, goats, cattle, humans and mice revealed 99, 98, 95, 82 and 80% identity, respectively. Availability of cloned bighorn sheep CD18 cDNA should allow the molecular characterization of M. haemolytica Lkt-receptor interactions in bighorn sheep and other ruminants that are susceptible to this disease.     

Pharmacokinetic comparison of six anthelmintics in sheep,goats, and cattle

This study was initiated to determine whether a comparative pharmacokinetic (PK) approach could be used to expand the pool of approved anthelmintics for minor ruminant species. Accordingly, the PK profiles of six anthelmintics (levamisole, albendazole, fenbendazole, moxidectin, doramectin, and ivermectin) in sheep, goats, and cattle were determined. The PK values determined for each anthelmintic included T_max, T_last, C_max, AUC, AUC/dose, and C_max/dose. The results of this study demonstrate that a comparative PK approach does not show commonality in the way these six anthelmintics are individually processed by these three ruminants. While some drugs demonstrated identical PK profiles between sheep and goats, none of these drugs demonstrated PK profiles in sheep and goats comparable to the PK profiles found in cattle. The results from this study suggest drug approval across these three ruminants is not a viable concept. However, the resulting PK profiles for each combination of drug and ruminant species represents a new dataset that can be used to support the US FDA Center for Veterinary Medicine's Minor Use/Minor Species indexing process for drug approvals in minor species such as sheep and goats.     

Chiral behaviour of the metabolite albendazole sulphoxide in sheep, goats and cattle

Three sheep, three goats and three cattle were dosed orally with 5.0, 7.5 and 10 mg albendazole kg-1 bodyweight, respectively. Blood samples were taken at intervals for 48 hours after administration. The enantiomeric ratio of the metabolite albendazole sulphoxide (SO.ABZ) was determined by liquid chromatography on chiral stationary phases. At To, the plasma concentration ratio (+)SO.ABZ/(-)SO.ABZ was estimated at 3.0 in sheep, 1.5 in goats and 4.0 in cattle. The proportion of the (+) enantiomer then increased linearly as a function of time during the course of the kinetics. In comparison to the area under the curve for total SO.ABZ, the (+) enantiomer represented 86 per cent in sheep, 80 per cent in goats and 91 per cent in cattle. The specific behaviour of the two enantiomers is probably the result of the enantioselectivity of the flavine adenosine dinucleotide and cytochrome P450 dependent enzymatic systems which are involved in the sulphoxidation and the sulphonation of ABZ.     

Absence of hypobiosis in abomasal nematodes of sheep and goats in Egypt

A total of 96 abomasa from sheep and goats at the Zagazig abattoir, Sharkia Province, Egypt, were examined, during the four climatic seasons from April 1986 to March 1987, for the presence of adult and larval nematodes. Adults of Trichostrongylus axei were most numerous followed by adult Haemonchus contortus. Adult Ostertagia sp. and Parabronema skrjabini were less prevalent. There was no significant difference between sheep and goats in infection rates, but worm burdens of the nematodes other than Ostertagia sp. were significantly higher (P less than 0.05) in sheep than in goats. The animals were uniformly infected with these parasites throughout the year as there were no significant differences in the incidence or intensity of infections between the four seasons. The numbers of larvae recovered from the wall of the abomasa were small in relation to the total adult worm population throughout the year with a slight increase during the summer. Hypobiosis, therefore, seems not to be important in the life cycle of abomasal nematodes of sheep and goats in Sharkia Province, Egypt.     

Avermectin-resistance in gastrointestinal nematodes of Boer goats and Dorper sheep in Switzerland

Anthelmintic resistance in gastrointestinal nematodes among small ruminants is widespread in South Africa and Dorper sheep and Boer goats have been imported into Switzerland from this country on a number of occasions. Therefore, this study aimed to investigate the occurrence of avermectin (AVM) resistant gastrointestinal nematodes (GIN) in these breeds in Switzerland. A total of 24 Boer goat farms and 12 Dorper sheep farms participated in the study. According to the faecal egg count reduction test (FECRT) AVM-resistant GIN populations were confirmed in 7 of the 24 Boer goat farms and suspected in a further 8 farms. Likewise AVM-resistance was confirmed in 2 of 12 Dorper sheep farms and suspected in a further 6 farms. Haemonchus contortus and Trichostrongylus spp. were the dominant resistant species according to larval cultures. In the farms with detected AVM-resistance the animals were additionally treated with levamisole after natural reinfection. With the exception of one farm with a 'close-to cutoff-result' the FECRT gave no indication for resistance against levamisole. The results indicate that AVM-resistance is widespread in Swiss small ruminant farms keeping Boer goats and Dorper sheep. The common tradition of grazing animals from different farms on prealpine and alpine pastures could favour the spread of resistant populations within the country.