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This is a cross-sectional study to assess the presence of antibodies in ruminants against selected pathogens associated with reproductive disorders in cattle in four Brazilian states, including the zoonotic agent Coxiella burnetii. The used tests were Virus Neutralization Assay for IBR and BVD, Microscopic Agglutination Test for Leptospira spp., Indirect Fluorescent Antibody Test (IFAT) for C. burnetii and Toxoplasma gondii, and Enzyme-Linked Immunosorbent Assay for Neospora caninum and Trypanosoma vivax. Seropositivity for C. burnetii was 13.7% with titers from 128 to 131,072; 57.8% for BoHV-1, with titers between 2 and 1,024; 47.1% for BVDV-1a, with titers from 10 to 5,120; 89.2% for N. caninum; 50% for T. vivax; and 52.0% for Leptospira spp., with titers between 100 to 800 (the following serovars were found: Tarassovi, Grippotyphosa, Canicola, Copenhageni, Wolffi, Hardjo, Pomona and Icterohaemorrhagiae); 19.6% for T. gondii with titer of 40. This is the first study that has identified C. burnetii in cattle associated with BoHV and BVDV, N. caninum, Leptospira spp., T. gondii and T. vivax. Thus, future studies should be conducted to investigate how widespread this pathogen is in Brazilian cattle herds.

Background: The measure of anaemia status using packed cell volume (PCV) can be a reliable indicator of African trypanosomosis (AT) in the absence of other anaemia-causing conditions. However, studies that have estimated prevalence of anaemia in cattle from AT endemic areas have rarely reported the prevalence of the disease in the anaemic cattle. Therefore we investigated the prevalence of AT in anaemic cattle at sites that had recently reported the disease in Itezhi tezhi district of central Zambia., Methods: During a survey, blood samples were collected from 564 randomly selected cattle for anaemia determination from seven crush pens (Mutenda, Kapulwe, Banachoongo, Itumbi, Iyanda, New Ngoma and Shinampamba). At a PCV- value cut off of 26 %, all samples positive for anaemia were subjected to both parasitological examination on thick and thin blood smears and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) for detection of trypanosome DNA. Fisher's exact test and a mixed effect logistic regression analyses were used to determine and measures associations, respectively., Results: Of 564 cattle screened, 58 (10.3 %; 95 % CI: 7.8-12.8 %) had anaemia. PCR-RFLP results showed that 17 (29.3 %; 95 % CI; 17.2-41.4 %) anaemic cattle were positive for pathogenic trypanosomes compared to 1 (1.7 %; 95 % CI: 0.0-5.2 %) on parasitological examination using thick smears. The infections were caused by Trypanosoma congolense and Trypanosoma vivax. Fisher's exact test showed a strong association between PCV and pathogenic trypanosome infection (P = 0.004). A mixed effect multivariate logistic regression showed that a one unit increase in PCV reduced the likelihood of detecting AT with PCR-RFLP by 24.7 % (95 % CI: 4.6-40.6 %; P = 0.019) in anaemic cattle, taking into account their age and sex, with random effects for crush pen., Conclusion: These results suggest that T. congolense and T. vivax could be important causes of anaemia in cattle reared in AT endemic areas of Itezhi tezhi in Central Zambia. This also suggests that even though pathogenic trypanosomal infection was strongly associated with PCV, it could only account for up to 41 % of the anaemia in cattle. Therefore further investigation to ascertain other factors responsible for anaemia in AT endemic areas of Itezhi tezhi in Central Zambia is needed.

The effects of experimental Trypanosoma congolense infection in Gambian N'dama and Gobra zebu cattle on number of naturally-occurring adult ticks attaching were studied. An indirect fluorescent antibody test was performed to detect serological prevalence of Cowdria ruminantium antibody. The intravenously imposed trypanosome infection did not result in significant (P > 0.05) differences in Amblyomma variegatum and Hyalomma spp. infestations between control and infected N'dama cattle. Control N'damas carried significantly (P < 0.001) lower numbers of A. variegatum and Hyalomma spp. than the control zebus. Serological frequency of C. ruminantium antibody was similar in both control or infected N'dama and in control or infected zebu cattle. No deaths occurred among N'dama cattle, while all six trypanosome infected zebus progressively died within nine weeks post-infection but trypanosomosis was excluded as the primary cause of death. Examined Giemsa-stained blood smears were negative for the presence of tick-borne micro-organisms. Four positive cases of cowdriosis were identified during post-mortem examination. It was concluded that N'damas, even when submitted to trypanosome infection, react consistently better than Gobra zebus to tick attachment. These results emphasize the benefits of rearing disease resistant cattle breeds, such as N'dama, in areas where risks of trypanosomosis and cowdriosis coexist.

Strongyle faecal egg output was estimated in N'Dama, Zebu and N'Dama x Zebu crossbred (F1) cattle. N'Dama cattle showed a significantly lower prevalence of strongyle infection, as measured by faecal egg output, than F1 (P < 0.01) and Zebu (P < 0.001) cattle. In strongyle-infected animals, mean egg output was also significantly lower in N'Damas (P < 0.03) than in Zebus. A previous trypanosomiasis infection did not affect the results. The presence of a natural resistance trait to strongyle infection in N'Dama cattle is postulated.

148 one-year-old N'Dama cattle, progeny of 29 sires, were exposed for 92 days to a medium natural tsetse-trypanosome challenge in Gabon, Central Africa. Matching health and performance data were recorded on 11 occasions. Average packed red cell volume percent (PCV) and lowest PCV reached during the period were evaluated as measures of ability to control the development of anaemia. Attempts were made to systematically control other possible causes of anaemia. In animals detected as parasitaemic, those with above average average PCV values or above average lowest PCV reached had 34% and 35% respectively higher daily weight gains than those with below average. Even when not detected as parasitaemic, those with above average average PCV values or above average lowest PCV reached had 14% and 12% respectively higher gain indicating that a proportion of these animals actually were parasitaemic. When all environmental and parasitaemia information was taken into account, the heritability of growth, average PCV and lowest PCV reached was 0.39 +/- 0.31, 0.64 +/- 0.33 and 0.50 +/- 0.32 respectively. The genetic correlation between average PCV and growth was 0.70 +/- 0.42 and between lowest PCV reached and growth was 0.28 +/- 0.55. While the standard errors are large, the higher heritabilities of PCV measures compared to animal growth and the positive genetic correlations between PCV and growth do indicate an opportunity for selection on PCV when animals can be detected as parasitaemic. All heritabilities and genetic correlations increased in size when parasitaemia information was utilized in the analysis.(ABSTRACT TRUNCATED AT 250 WORDS)

Five crossbred cattle infected with Trypanosoma vivax (Likoni) by Glossina morsitans developed capillary haemorrhages at the onset of parasitaemia, followed by the presence of occult blood in faecal samples and eventually melena. Two animals required treatment to survive, on days 13 and 38 respectively. The other three animals cleared their parasitaemias without treatment. Packed cell volume (PCV) levels decreased in all animals to levels ranging from 7.5 to 17%. Relapse in a treated animal initiated marked haemorrhage and a loss of 14 PCV units during a six-day period. Thrombocytopenia was common to all animals, and thrombocytes decreased to levels of 4000/microliters of blood. All animals developed increased levels of fibrinogen and fibrin monomer. Prolonged prothrombin times were found in all animals, and activated partial thromboplastin times were also extended in the two animals with high parasitaemias.

Early during the course of Trypanosoma congolense infection in cattle decreases in PCV occurred and coincided with increases in both MCV and MCH. The indices reached highest levels between eight and 12 weeks post-infection. By week 20 of infection MCV and MCH had decreased to pre-infection levels even though a substantial anemia persisted. Serum iron levels were elevated at eight weeks postinfection. (Infected 271 mg dl-1 v. control 140 mg dl-1) but decreased to low levels in infected animals by Week 28 (63 mg dl-1). At eight weeks post-infection PITR was elevated in infected animals (infected 2.6 mg dl-1 day-1 v. control 0.82 mg dl-1 day-1). By Week 28, however, PITR had fallen in infected animals to 0.62 mg dl-1 day-1 indicating a severe dyshaemopoesis since PCV levels averaged only 22%. Cattle which were treated with Berenil or that self-cured the infection had normal iron parameters when tested 61 weeks post-infection. Cattle treated early during the course of infection showed a significantly greater PCV response that those treated later during infection.

Pseudo-lumpy skin disease and acute Trypanosoma vivax infections occurred simultaneously in a dairy herd which had no previous history of trypanosomiasis. The onset of the outbreak was sudden and 29 out of the 40 adult Friesian and exotic x zebu cattle were found to have skin lesions. Five out of the nine animals sampled had fulminating T. vivax parasitaemias with packed red cell volumes ranging from 0.09 to 0.28 litres/litre. Whereas carried tsetse may have introduced T. vivax, the failure to trap tsetse and the presence of large numbers of biting flies strongly suggested that in this outbreak both aetiological agents were transmitted mechanically.

Infection of Ayrshire cattle with a stock of Trypanosoma vivax from the Galana Ranch, Kenya, resulted in an acute disease characterised by profound anaemia and haemorrhage, which reached maximum severity between 3 and 5 weeks after infection. Bleeding from the ears, nose and rectum occurred. At necropsy, petechial and ecchymotic haemorrhages were widespread, but were particularly severe in the gastrointestinal tract. In confirmation of the gross findings, congestion, haemorrhage and degenerative changes in most tissues and organs were found histologically. Thrombi were seen in the lymphatic vessels and clots of fibrin were present in the ventricles of the brain. The anaemia was a consequence of frank blood loss through haemorrhaging, exacerbated by erythrophagocytosis of deformed red blood cells, whose occurrence was indicative of microangiopathic changes. Animals were euthanised between 23 and 36 days after infection when they became recumbent with PCV values as low as 9%. There is no doubt that animals affected by this syndrome in the field would die within a few weeks of infection, if left untreated.