The reservoir status of goats recovered from heartwater

Experiments were conducted with Creole goats and Amblyomma variegatum ticks in Guadeloupe to investigate whether it is possible to transmit Cowdria ruminantium to susceptible hosts with nymphs fed in the larval stage on recovered goats. Of 88 batches of larvae fed after the return of the goats' temperature to normal, or after challenge or immunosuppression, only the 9 batches of larvae fed during the febrile reaction, 2 batches applied 2 and 3 days respectively after recovery, and a single batch applied 5 days after challenge, became infective. On average, blood appears to be infective for A. variegatum larvae for only an 8-day period associated with the temperature reaction following a primary infection. Recovered goats are not reservoirs of Cowdria, even if--with one exception in our experiment--they are reinfected after recovery.     

Reduction in mortality from heartwater in cattle, sheep and goats exposed to field challenge using an inactivated vaccine

Inactivated vaccines for heartwater prepared with the commercially acceptable Montanide ISA 50 (ISA 50) adjuvant were field tested in Boer goats in Botswana, Angora goats in South Africa, and Merino sheep in Zambia and Zimbabwe. Two vaccines, one made using the Zimbabwean Mbizi isolate and the other using the respective local field isolate (Sunnyside in Botswana; Bathurst in South Africa; Lutale in Zambia), were tested at each site, except in Zimbabwe where only the Mbizi vaccine was tested. Compared with unvaccinated animals, the Mbizi vaccine significantly protected goats and sheep against field Amblyomma tick challenge in Botswana, Zambia and Zimbabwe (P = 0.018, 0.002 and 0.017, respectively), but failed to protect Angora goats in South Africa. However, in South Africa the vaccine prepared using the local field isolate Bathurst, induced significant protection (P=0.008). The vaccines containing the local isolates at all other sites were less protective than the Mbizi vaccine. The Mbizi inactivated vaccine also significantly protected 17 of 21 cattle (P = 0.05) against heartwater challenge from field ticks in Zimbabwe. Against the same challenge only 7 of 21 unvaccinated control cattle survived.This study demonstrates that heartwater is a major constraint to upgrading livestock in endemic areas, and caused an overall mortality of 77.6% in naive sheep and goats (97 of 125 died) and 67% in cattle (14 of 21 died). In contrast, the vaccine had a protective effect by reducing the overall mortality in sheep and goats to 54.3% (113 of 208 died) and to 19% in cattle (4 of 21 died).     

The non-specific resistance of cattle to heartwater

A distinction is drawn between the non-specific resistance to heartwater of very young calves and that of cattle older than a year. The suckling-calf resistance is at its greatest during the first few weeks after birth and then gradually declines during the next 6-8 months. Aspects of its possible mechanism and significance are discussed. The role played by conglutinin in the natural resistance of older cattle to heartwater and in the epidemiology of the disease in discussed.     

Genotypic characterisation of Indian cattle, buffalo and sheep isolates of Echinococcus granulosus

Twelve isolates of Echinococcus granulosus, collected from domestic animals, including cattle, buffalo and sheep were analysed for DNA nucleotide sequence variation within mitochondrial cytochrome c oxidase I (coxI), NADH dehydrogenase subunit I (nadI) and internal transcribed spacer gene I (ITS1). After analysis of sequence information this was found that the fragment size of ITS1 of buffalo isolate was more in comparison to cattle and sheep isolates. Based on the nadI genotype this was found that Indian cattle, buffalo and sheep isolates could be grouped into E. granulosus sensu stricto. Based on coxI genotype two sheep isolates and one buffalo isolate were homologous to G2 genotype. Rests of the isolates were microvariants of G2 genotype. Presence of G2 genotype in buffalo is the first report of this genotype from this host.     

The airborne dispersal of foot-and-mouth disease virus from vaccinated and recovered pigs, cattle and sheep after exposure to infection.

Foot-and-mouth disease virus was detected during two periods in the air of looseboxes which housed susceptible, vaccinated or recovered pigs, cattle or sheep exposed to infection. The first was 30 min to 22 h after exposure and occurred in all animals. The second was two to seven days after exposure and occurred with those susceptible and vaccinated animals which developed clinical lesions, and with vaccinated and recovered pigs and sheep, which did not develop clinical lesions. Vaccination of animals before exposure resulted in less or no virus being detected. The virus during the first period was attributed to virus trapped on the animal during exposure, and the virus during the second period to limited multiplication in the respiratory tract. Control of movement for two weeks after contact with infection is suggested as a means of preventing spread of foot-and-mouth disease in areas that contain vaccinated animals.     

Oxyclozanide—Activity against fasciola gigantica in naturally infected buffalo,cattle, sheep and goats

Summary The activity of oxyclozanide was studied in buffalo, cattle, sheep and goats naturally infected withFasciola gigantica. The results indicate a very high efficiency against flukes aged six weeks or more. The drug was also observed to have considerable action on hepatic and ruminal amphistomes. No toxic side-effects were observed in any of the animals treated, except slight softening of faeces with increased frequency of defaecation and inappetance in a few animals. This was observed more frequently in buffalo than in cattle. Sheep and goats were less affected. A transient drop in milk yield for about two to three days was observed in a few animals. No ill effects were observed in experimental animals which were maintained on highly nitrogenous diets. The drug was also well-tolerated by pregnant animals.

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Sumario Se estudió la actividad del oxyclozanide en búfalos, bovinos, ovinos y caprinos infectados naturalmente conFasciola gigantica. Los resultados indican una eficiencia muy alta contra Fasciolas de 6 semanas ó mas. La droga tuvo también una acción considerable sobre los amfistomas hepáticos y ruminales. No se observaron efectos colaterales tóxicos en los animales tratados, excepto por el ligero ablandamiento de las heces con un incremento de la frecuencia en la defecación e inapetencia en algunos animales. Esto se observó mas frecuentemente en búfalos que en bovinos. Los ovinos y caprinos fueron menos afectados. Se observó una disminución transitoria en la producción de leche de algunos animales la cual duró de dos a tres dias. No se observaron efectos nocivos en los animales en experimentación que fueron mantenidos con dietas altas en nitrógeno. La droga fué tolerada bastante bien por animales en gestación.

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Résumé L'activité de l'oxyclozanide a été étudiée chez les buffles, les bovins, les moutons et les chèvres naturellement infestés parF. gigantica. Les résultats révèlent une trés haute efficacité contre les douves agées de six semaines ou plus. Ce produit se montra aussi très actif sur les amphistomes du foie et du rumen. Aucun effet toxique associé ne fut observé chez les animaux traités, excepté un léger ramollissement des fèces, un accroissement de la fréquence des défécations et de l'inappétence chez un petit nombre d'animaux. Cela fut observé plus souvent chez les buffles que chez les bovins. Chèves et moutons furent moins affectés. On observa chez quelques animaux une baisse temporaire de la production lactée durant deux à trois jours. Aucune réaction défavorable n'apparut chez les animaux d'expérience soumis à régime à forte teneur en azote. Le produit est aussi bien toléré par les femelles en gestation.

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Oxyclozanide is a product of Imperial Chemical Industries (trade name ‘Zanil’).     

Vitamin E status of cattle and sheep. 2: Survey of liver from clinically normal cattle and sheep for alpha-tocopherol

Analysis of liver from clinically normal animals showed a mean alpha-tocopherol level of 20 mg/kg for cattle and 6 mg/kg for sheep. The corresponding normal values (mean +/- 2 S.D.) were 9 to 44 mg/kg and 1.8 to 20 mg/kg. The usefulness and assessment of tocopherol analyses on liver and serum samples are discussed in the light of these normal values and routine diagnostic submissions.     

Protection of goats against Caribbean and African heartwater isolates by the Ball 3 heartwater vaccine

Summary Two groups of castrated male adult goats (three goats/group) were infected intravenously with the Ball 3 vaccine strain ofCowdria ruminantium and treated with long-acting oxytetracycline at the onset of clinical disease 10 days later. Five weeks post-vaccination one group was challenged with a Caribbean isolate (Gardel) and the other group with a West African isolate (Mali) ofC. ruminantium. Non-vaccinated controls infected with either the Gardel or Mali isolate died. All of the vaccinated animals challenged with the Gardel strain reacted and survived. The three vaccinated animals challenged with the Mali isolate also reacted and two died of heartwater.

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Proteccion De Cabras Con La Vacuna Ball 3 Contra Las Cepas Caribeña Y Africana Causantes De Hidropericardio

Resumen Se infectaron tres grupos de machos cabríos castrados vía intravenosa (tres cabras/grupo), con la vacuna Ball 3 deCowdria ruminantium. Los animales se trataron posteriormente con tetraciclina LA, diez días después al comienzo de la enfermedad clínica. Cinco semanas después de la vacunación, un grupo se descargó con la cepa Caribeña (Gardel) y el otro grupo, con la cepa Africana Occidental (Malí) deC. ruminantium. Los controles no vacunados, infectados con las cepas Gardel y Malí, murieron. Todos los animales vacunados que recibieron la descarga con la cepa-Gardel, sobrevivieron. Los tres animales que recibieron la descarga con la cepa Malí reaccionaron también, muriendo dos de ellos.

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Protection Apportee Aux Chevres Vis-A-Vis Des Souches antillaises Et Africaines De Heartwater Par Le Vaccin Heartwater Ball 3

Résumé Deux groupes de chèvres adultes (mâles castrés, 3 animaux par groupe) ont été infectés par voie intraveineuse avec la souche vaccinale Ball 3 deCowdria ruminantium, et traités avec une oxytetracycline à longue action lors de l'application des signes cliniques dix jours plus tard. Cinq semaines après la vaccination, un groupe a été éprouvé avec une souche antillaise (Gardel) et l'autre groupe avec une souche ouest-africaine (Mali) deC. ruminantium. Les animaux contrôlés, non vaccinés, infectés soit par la souche Gardel, soit par la souche Mali, sont morts. Les animaux vaccinés, éprouvés avec la souche Gardel ont réagi mais ont survécu. Les trois animaux éprouvés avec la souche Mali ont aussi réagi et deux sont morts de heartwater.

     

Potential for the transmission of foot-and-mouth disease virus from African buffalo (Syncerus caffer) to cattle

Foot-and-mouth disease viruses of types SAT 1 and SAT 2 isolated from diseased cattle and carrier buffalo, either on the same farm or in the same ecological area within a short time of each other, were compared by T1 oligonucleotide mapping. No similarity was observed between the maps obtained, indicating that the different populations of virus were unique to each species and that no interspecies transmission had occurred.     

Histophilus somni IbpA Fic cytotoxin is conserved in disease strains and most carrier strains from cattle, sheep and bison

Histophilus somni causes bovine pneumonia, septicemia, myocarditis, thrombotic meningoencephalitis and arthritis, as well as a genital or upper respiratory carrier state in normal animals. However, differences in virulence factors among strains are not well studied. The surface and secreted immunoglobulin binding protein A (IbpA) Fic motif of H. somni causes bovine alveolar type 2 (BAT2) cells to retract, allowing virulent bacteria to cross the alveolar monolayer. Because H. somni IbpA is an important virulence factor, its presence was evaluated in different strains from cattle, sheep and bison to define whether there are syndrome specific markers and whether antigenic/molecular/functional conservation occurs. A few preputial carrier strains lacked IbpA by Western blotting but all other tested disease or carrier strains were IbpA positive. These positive strains had either both IbpA DR1/Fic and IbpA DR2/Fic or only IbpA DR2/Fic by PCR. IbpA Fic mediated cytotoxicity for BAT2 cells and sequence analysis of IbpA DR2/Fic from selected strains revealed conservation of sequence and function in disease and IbpA positive carrier strains. Passive protection of mice against H. somni septicemia with antibody to IbpA DR2/Fic, along with previous data, indicates that the IbpA DR1/Fic and/or DR2/Fic domains are candidate vaccine antigens for protection against many strains of H. somni. Since IbpA DR2/Fic is conserved in most carrier strains, they may be virulent if introduced to susceptible animals at susceptible sites. Conservation of the protective IbpA antigen in all disease isolates tested is encouraging for development of protective vaccines and diagnostic assays.     

Infection of African buffalo (Syncerus caffer) and cattle with Theileria parva lawrencei after serial passage in cattle

The infectivity of a Theileria parva lawrencei stabilate, from a stock derived from an African buffalo (Syncerus caffer) in the Serengeti National Park, Tanzania, was investigated. In the first experiment a buffalo and three cattle were inoculated with a stabilate from a stock passaged three times in cattle. All cattle developed fatal theilerial infections. Isolations from the buffalo by tick feeding and cell culture isolation showed that it was infected with T p lawrencei at the time of inoculation, but the second isolation made 19 days after inoculation behaved like T p parva in cattle, developing a high parasitosis, while the third isolation made three months later behaved like T p lawrencei with low parasitosis. It was concluded that two biological types of T parva could exist in a buffalo at one time, but it was not shown that the buffalo had become a carrier of T p lawrencei adapted to cattle. In the second experiment two buffaloes and three cattle were inoculated with T p lawrencei (Serengeti) stabilate which had been passaged six times through cattle and ticks. The two buffaloes had mild theilerial infections and developed serological titres in the indirect fluorescent antibody test, but the cattle had fatal infections. Tick and cell culture isolations of T parva were possible during the clinical reactions of the buffaloes, but no carrier state was demonstrated. Theileria-infected cell lines were established from the buffaloes and the cattle and were examined using monoclonal antibodies against T parva schizonts.(ABSTRACT TRUNCATED AT 250 WORDS)     

Susceptibility of African buffalo and Boran cattle to Trypanosoma congolense transmitted by Glossina morsitans centralis

Four African buffalo (Syncerus caffer) and four Boran cattle (Bos indicus) were each exposed to the bites of 10 tsetse flies infected with Trypanosoma congolense. Although both groups of animals became infected, the buffalo showed no clinical signs of trypanosomiasis while the cattle suffered from the disease characterized by pronounced skin reactions, high parasitaemia and severe anaemia. The prepatent periods in the buffalo varied from 18 to 27 days in comparison with 11 to 14 days in the cattle. In the buffalo, skin reactions were only detectable by histological examination of skin biopsies, the peak of parasitaemia was at least a hundredfold below that in cattle and after 54 days parasites were no longer detected. In contrast, the cattle had a continuous high parasitaemia until they were treated with a trypanocidal drug 60 days after infection. Neutralizing antibody to metacyclic trypanosomes appeared in the buffalo during the prepatent period, 15-20 days after infection, whereas in cattle neutralizing antibody was not detected until 10 days after the first peak of the parasitaemia, 25-30 days after infection.     

The presence of endotoxin activity in cases of experimentally-induced heartwater in sheep

The presence of endotoxin was examined in 5 sheep with experimentally-induced heartwater. Two peaks in endotoxin levels were recorded in 4 out of the 5 sheep during the acute stage of the disease. The 1st peak coincided with or occurred shortly after the febrile reaction (over 40 degrees C). The 2nd peak occurred 3-5 days after the 1st, and in 2 sheep this 2nd elevation in endotoxin levels was associated with severe clinical signs (rapid and laboured breathing, cyanosis and recumbency), and 1 of the 2 sheep died on the day of the 2nd elevation. Both endotoxin peaks were of short duration and levels had decreased in the 24-h follow-up samples.     

The foot-and-mouth disease risk posed by African buffalo within wildlife conservancies to the cattle industry of Zimbabwe

Quantification of the risk that African buffalo (Syncerus caffer) (isolated within wildlife conservancies in Zimbabwe by a double fencing system) would infect cattle outside the conservancies with foot-and-mouth disease (FMD) virus was assessed by scenario-pathway analysis. Of the five scenarios considered, the greatest annual risk (1:5000) for cattle would be from antelope jumping over the outer perimeter fence of the conservancy and infecting cattle on the outside. The other transmission scenarios (including air-borne transmission) had a FMD risk that was low to very low. Risk management would include means to prevent the escape of antelope from the conservancies and restriction of cattle density in the proximity of the perimeter fence.