Parasitological and clinical responses of lambs experimentally infected with Haemonchus contortus (L3) with and without ivermectin treatment

Haemonchus contortus is one of the most important parasites that infects sheep and exerts its pathogenic effects by sucking blood, causing disturbances of organ-functions and thus inducing alterations in various normal physiological parameters. Changes in live body weight, faecal egg count, kinetics of circulating eosinophils and PCV value were studied at weekly interval for a period of 84 days in 18 lambs of local breed after infection with a single dose of 5000 H. contortus (L(3)). In the two groups of lambs infected with nematodes both non-treated and treated with ivermectin (HcNT and HcIT), similar egg excretion patterns was observed starting from third week after infection, with a regular increase in FEC. Examination of whole abomasum of each animal revealed no developmental stage of nematode from treated and control lambs on day 84. The total mean number of H. contortus worms recovered at necropsy from abomasa of untreated infected lambs (group HcNT) was 2576.2 (+/-221.0). The significant loss of body weight, development of heavy worm burden and severe anaemia as indicated by reduced PCV in untreated infected lambs indicated high susceptibility of the lambs to H. contortus. On the other hand, complete absence of the parasite, improved PCV value and body weight after treatment of infected animals (HcIT) proved 100% efficacy of ivermectin against H. contortus.

The effect of gastrointestinal parasitism on blood copper and hemoglobin levels in sheep

Endoparasitism is a problem in Trinidad, as it is in most tropical countries. Parasite infection has been suspected to contribute to the pathogenesis of swayback disease (which is also prevalent in Trinidad), but the mode of action has not been clearly defined, although it has been suggested that parasites interfere with the absorption of copper from the gastrointestinal tract. The objectives of the study were to assess the effect of endoparasitism on blood copper levels and hemoglobin (Hb) concentration in sheep in Trinidad. Copper was administered intramuscularly to parasite infected and noninfected animals. The results showed that parasitism has a depressing effect on blood copper and Hb levels, even when administered parenterally. It is concluded that parasitism can aggravate existing hypocupremia and possibly influence the expression of swayback disease.

Ethnoveterinary medicines used for ruminants in Trinidad and Tobago

Ethnoveterinary research was conducted in Trinidad and Tobago in 1995, in order to document existing ethnoveterinary practices. This paper describes 20 medicinal plants and used to treat ruminants. The main plants used were Azadirachta indica and Curcuma longa. Medicinal plants were used predominantly for endoparasities, internal and external injuries and pregnancy-related conditions. A 4-stage process was used to conduct the research and document the ethnoveterinary practices. This documentation could provide a foundation for the further scientific study and verification of those practices which merit such study(AU)

Serological survey of leptospirosis in livestock animals in the Lesser Antilles

A serological survey was performed of 1788 cattle, goats and sheep on 13 islands in the Lesser Antilles. Sera were tested by microscopic agglutination (MAT) using a panel of 22 live antigens. Evidence of past exposure, at a titer of > or = 100, was found in 101 animals (5.6 percent). Antibodies were more common in cattle and goats (7.2 percent in each) than in sheep (1.7 percent). Seroprevalence was highest in cattle in Martinique (20 percent) and in goats in St. Vincent (23 percent). The predominant serogroups were Sejroe (largely confined to cattle in Martinique), Autumnalis, Icterohaemorrhagiae, Grippotyphosa, and Cynopteri. Eleven cattle from Martinique and 2 sheep with titers of > or = 800 showed evidence of recent infection. (AU)

Ovine trypanosomosis: a seroepidemiological survey in coastal Guyana

The objective of this study was to determine the seroprevalence rates of Trypanosoma vivax and Trypanosoma evansi in sheep in coastal Guyana. Blood samples were taken from a systematic random sample of one hundred and ninety-three (193) sheep on twenty-two (22) farms in Region 5, Mahaica/Berbice, a coastal area of Guyana. Age, breed, sex, and farm of origin were recorded for all sampled sheep. One hundred and seventy-six (176) serum samples were submitted for Indirect Fluorescent Antibody (IFA) testing for T. vivax and T. evansi. Fluorescence was graded as 0 (negative), 1+(very weak), 2+(weak), 3+(strong) or 4+(very strong), as measured at 1:160 dilution of serum. Samples were considered to be sero-positive if any fluorescence was observed. Indirect Fluorescent Antibody results were received for one hundred and sixty-one (161) samples. One hundred and three (64 percent) sera were sero-positive for Trypanosoma sp. Of these, 38 (23.6 percent) sera were positive to T. evansi only, 11(6.8 percent) were positive to T. vivax only and 54 (33.5 percent) were positive for both. As cross reactions occur between T. vivax and T. evansi, it was difficult to determine the true species of exposure for the sera which tested positive to both species. The overall sero-prevalence rate of 64 percent suggests that trypanosomosis is endemic in sheep in coastal Guyana. This was the first serological evidence of T. evansi in Guyana. Although T. vivax is believed to be pathogenic in sheep, the clinical siginficance of T. evansi remains unknown. The vector of both species of trypansomes in sheep on the north of South America also is not known (AU)

Campylobacter infections in calves, piglets, lambs and kids in Trinidad

Faeces or rectal swabs from 689 diarrhoeic and non-diarrhoeic animals were cultured for thermophilic campylobacters and their antibiograms were determined. Three hundred and fifteen (45.7 percent) samples were positive for Campylobacter. Piglets had the highest prevalence, 79.3 percent (233/294) and lambs, the lowest with 17.9 percent (15/84) being positive. The difference was statistically significant (P < or = 0.01; chi 2). In calves, 20.5 (60/293) and in kids 38.9 percent (7/18) were positive for campylobacters. The prevalence of infection was not significantly (P > or = 0.05; chi 2) different between diarrhoeic (46.1 percent) and non-diarrhoeic (45.1 percent) animals nor between male (47.5 percent) and female (43.8 percent). The frequency of isolation of campylobacters harvested from semi-intensively managed animals (75.4 percent) was, however, significantly higher (P < or = 0.001; chi 2) than from intensively or extensively managed animals. Overall, C. coli strains (32.8 percent) were more frequently isolated than C. jejuni strains (12.9 percent) and the difference was significant (P < or = 0.001; chi 2). Biotype I accounted for 67.3 percent (152/226) of C. coli and 64.0 percent (57/89) of C. jejuni strains isolated. A total of 245 (77.8 percent) strains of Campylobacter exhibited resistance to one or more antibiotics and was highest to streptomycin (76.5 percent), kanamycin (28.6 percent) and neomycin (26.7 percent). It was concluded that Campylobacter infections were widespread in livestock in Trinidad, particularly C. coli in piglets. (AU)

The development of an enzyme-linked immunosorbent assay for Trypanosoma vivax and its use in a seroepidemiological survey of the Eastern Caribbean Basin

An enzyme-linked immunosorbent assay (ELISA) for IgG antibodies against a South American (New World) strain of Trypanosoma vivax was developed and used for mass screening of cattle from 20 islands in the Eastern Caribbean Basin. The sensitivity and specificity of antigens prepared from a bovine-derived field strain and a nurine-adapted laboratory strain of T. vivax, both of New World origin, were compared using an indirect fluorescent antibody (IFA) test, and an antigen prepared from murine-adapted strain was subsequently used to develop an ELISA test. The results of the ELISA test were then compared with the results of a concurrently run IFA test. There was no cross-reactivity with either test using serum from a Trypanosoma theileri-infected cow. Both tests were weakly cross-reactive with sera from a T. brucei-infected steer, and the IFA test was moderately cross-reactive with several serum samples from a T. evansi-infected steer. For bovine sera collected from herds on islands in the Eastern Caribbean region, only five of 640 tested positive with the ELISA test. Thirty five of 653 sera tested were positive by IFA although the fluorscence elicited was weak as compared to that elicited by sera from known infected animals. Sera collected from 27 cattle in a region known to be free of T. vivax (OH, U.S.A) were negative with the ELISA test, whereas seven of 30 sera from a herd in French Guiana known to be infected with T. vivax were positive. None of 45 caprine and 60 ovine sera collected from islands in the Eastern Caribbean region were positive by the IFA test, therefore an ELISA system for these species was not developed (AU)

Small ruminant trypanosomiasis in Guyana - a preliminary report [published erratum appears in Br Vet J 1990 Nov-Dec: 146(6): 581]

Trypanosomes identified as Trypanosoma vivax were found infecting nine sheep (4.6 percent) and one goat (1.3 percent) on four of 11 farms surveyed on coastal Guyana. Animals sampled on another farm situated in the Rupununi savannahs gave negative results. Haematological techniques preferred for studies of this nature were the hematocrit centrifuge technique (HCT) and the thick blood smear technique. (AU)

Serological studies on leptospirosis in livestock and chickens from Grenada

Sera from 1206 livestock animals and chickens in Grenada and Trinidad were tested for leptospiral antibodies by the microscopic agglutination test. 376 of the sera were positive (44 percent of those tested in Trinidad and 25 percent of those tested in Grenada). The positive sera were obtained from 25 percent of 324 cattle 35 percent of 130 pigs, 35 percent of 126 sheep, 25 percent of 44 goats, and 11 percent of 175 chickens in Grenada; and 92 percent of 26 cattle, 53 percent of 122 pigs, 76 percent of 86 horses, and 11 percent of 144 chickens in Trinidad. 8 sera from ducks and geese in Trinidad were tested and found to be negative. The serogroups most commonly found to react with sera of the Grenadian animals were Autumnalis, Icterohaemorrhagiae, Hebdomadis and the related serogroups Sejroe and Mini, and Pyrogenes; in the Trinidadian animals they were Icterohaemorrhagiae, Autumnalis, Hebdomadis and its related serogroups and Panama. Strains of serogroup Pomona do not appear to have become established as livestock pathogens on the islands (AU)

Fascioliasis in Jamaica: epidemiologic and economic aspects of a snail-borne parasitic zoonoses

This study attempts to quantify the animal health, veterinary public health, and economic impact of fascioliasis in Jamaica. A coprologic survey conducted for this purpose in late 1979 and early 1980 revealed an overall fascioliasis prevalence of at least 22.2 percent (n=520) in cattle and 17.2 percent (n=514) in goats. In general the prevalence of the disease was found to be directly correlated with rainfall and inversely correlated with altitude. Four ecological zones of endemicity were identified and related to the epidemiology of the intermediate host, Fossaria cubensis. The economic cost of the disease was estimated from production statistics and a questionnaire survey. Losses were categorised as either direct (due mainly to liver condemnation and suboptimal dairy or beef production) or indirect (due mainly to treatment costs). The estimate did not include the less quantifiable costs associated with mortality, provision of veterinary services, and lost opportunities for development. The total economic cost of fascioliasis in Jamaica, as indicated by the above data, appears to be on the order of J$2.4 million (J$1.78=US1.00); and if anticipated improvements in Jamaica's livestock industry are allowed for, this total rises to J$3.2 million. It is noteworthy that a significant share of this cost would be in scarce foreign exchange spent on drugs and on imported substitutes for local meat and dairy products. It should also be recalled that fascioliasis is a zoonosis producing significant numbers of human cases in the Greater Antilles, and that inappropriate changes in vegetable cultivation practices could cause it to become a significant health problem in Jamaica. Finally, there is a very real danger that proposed increases in Jamaica's cattle and sheep herds could enormously increase the prevalence of the disease, as has happened elsewhere. It is therefore recommended that development of the country's livestock industry be paralled by development of an appropriate fascioliasis control strategy. Such a planned approach to fascioliasis control, which tends to be relatively cost-effective, confines treatment to the periods and localities at greatest risk and uses animal management techniques to reduce the incidence of infection (Summary)

Nasal tumour in a sheep in Trinidad, West Indies

Medical treatment of a pregnant 3 to 4-year old Barbados Black Belly ewe with a swelling of the left face and from which there was a bloody nasal discharge was unsuccessful. Further clinical examination of the animal led to the suspicion of a malignant neoplasm. The animal was euthanised and a detailed post mortem examination was performed. Gross and histological examination revealed an adenocarcinoma of the nasal cavity with metastasis to the lungs. Tumours in sheep generally, and adenocarcinomas of the nasal cavity in particular, are of rare occurence (AU)

Copper deficiency in pregnant ewes: its influence on the course of pregnancy and the health status of the offspring

Swayback disease (SD) which affects young sheep and a number of other animals is caused by the unavailability of metabolizable copper during the last half of pregnancy. In an effort to increase the present understanding of the development of SD and related human disorders we induced copper deficiency in pregnant ewes and studied its effects on pregnancy and the offspring. Nineteen pregnant ewes were rendered copper deficient by injection of ammonium tetrathiomolybdate (ATM), at 1mg/Kg during (I)the last 8-11 weeks, (II)the last 4-6 weeks and (III)the last 1-2 weeks of pregnancy. Treatment was continued until the lambs were weaned and sacrificed. Atomic absorption spectroscopy revealed that prolonged ATM treatment causes unpredictable changes in serum copper levels in the pregnant ewes, varying from large increases of 133 percent to large decreases of 65 percent. An unusually high number of treated ewes (29 percent) died during pregnancy. Neonates from ewes of the 1-2 week treatment group had normal serum copper levels, while 86 percent of the lambs from the 4-8 week group displayed subclinical serum copper levels (<0.5 ppm). Lambs from ewes in the 8-11 week group had serum copper levels ranging from moderate, 0.6 ppm to very high, 3.4 ppm. Nine of the 22 offspring showed signs of SD: none of these were from ewes receiving ATM treatment for the shortest period: 44 percent of the lambs from the intermediate group and 63 percent of those from the group receiving the longest ATM treatment were diseased. We conclude that while copper deficiency occuring in the last two weeks of pregnancy appears to have no effect, acute deficiency occuring at earlier stages, particularly the last 8-11 weeks, is likely to precipitate swayback disease in the offspring. Finally, it has been suggested that the early postnatal development stage of the human, corresponds to the final prenatal stage of the lamb, the present findings therefore suggest that the human foetus might be susceptible to copper deficiency even during the final weeks of pregnancy (AU)