Serological studies of babesiosis and anaplasmosis of cattle

SUMMARY Bos indicus-crossbred calves exposed to natural Babesia bovis infection in wet and dry tropical environments in northern Queensland were tested for antibodies using the indirect haemagglutination (IHA) test. There was evidence of maternal antibodies suggesting endemicity of B. bovis in the 2 environments. Within one year 35.3 to 94.6% of the calves had acquired B. bovis infection. The highest titres and most rapid conversion rates were observed just after the wet season when the tick population was at its peak. Clinical disease was not observed.     

Suppression of bovine lymphocyte responses to mitogens following in vivo and in vitro treatment with dexamethasone.

Gnotobiotic calves given intramuscular injections of dexamethasone (DM, 0.5 mg kg-1 day-1) showed marked changes in haematological parameters including a neutrophilia and a lymphopaenia. Not only was there a reduction in the numbers of circulating mononuclear cells, but there was also a significant (P less than 0.01) decrease in the in vitro responsiveness of the remaining circulating peripheral blood lymphocytes to the mitogens, phytohaemagglutinin (PHA), concanavalin A (ConA) and pokeweed mitogen (PWM). Responses to all three mitogens were suppressed to a similar degree. Analysis of the circulating mononuclear cell sub-populations before and during DM treatment demonstrated a selective depletion of B cells; the T lymphocyte sub-population that expresses the gamma/delta form of T cell receptor, are CD2-, CD5+, CD8-, CD4- and constitute a major population in peripheral blood of calves. In vitro studies in gnotobiotic and conventional calves confirmed that DM was highly inhibitory for PHA responses but, in contrast to the in vivo findings, showed little effect of DM on ConA responses. Expression of surface antigens after 72 h in vitro culture in the presence of DM were little affected with the exception of BoCD8 and MHC II, which showed increased and decreased expression, respectively. These observations would suggest that distinct mechanisms are involved in glucocorticosteroid suppression of the responses to these two mitogens.     

Comparative efficacy of drugs in bovine anaplasmosis

Summary Calves experimentally infected withAnaplasma marginale were subjected to chemotherapeutic treatment in groups, each group receiving one drug only. Observations were made on clinical signs, haematological changes, parasitaemias and levels of antibodies as measured by the complement fixation test. The most effective treatment was with imidocarb; other drugs which were apparently effective were steclin, terramycin and aureomycin in that order, while chloroquin diphosphate and camoquin gave little indication of therapeutic value.

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Eficacia Comparativa De Drogas En La Anaplasmosis Bovina

Resumen Diferentes grupos de terneros infectados conAnaplasma marginale se sometieron a tratamientos quimioprofilácticos con una droga específica cada uno. Se observaron los síntomas clínicos, cambios hematológicos, parasitémias y niveles de anticuerpos, estos últimos mediante la prueba de fijación de complemento. El tratamiento más efectivo fue con imidocarb y en orden decreciente con esteclin, terramicina y aureomicina. El difosfato de cloroquin y el camoquin no tuvieron valor terapéutico.

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Efficacite Comparee De Medicaments Contre L'anaplasmose Bovine

Résumé Des veaux expérimentalement infectés parAnaplasma marginale ont été soumis à des traitements chimiothérapiques de groupe, chacun de ces groupes ne recevant qu'un seul des produits essayés. Les observations ont parté sur les signes chimiques, les variations dans les formules hématologiques, la parasitémie et le niveau des anticorps mesurés par la réaction de fixation du complément. Le traitement le plus efficace a été obtenu avec l'imidocarbamide; les autres corps qui ont été apparemment efficaces ont été: steclin, terramycine et aureomycine dans cet ordre, alors que le diphosphate deichloroquine et al camoquine n'ont paru avoir qu'une action thérapeutique très limitée.

     

Comparative efficacy of drugs in bovine anaplasmosis

Calves experimentally infected with Anaplasma marginale were subjected to chemotherapeutic treatment in groups, each group receiving one drug only. Observations were made on clinical signs, haematological changes, parasitaemias and levels of antibodies as measured by the complement fixation test. The most effective treatment was with imidocarb; other drugs which were apparently effective were steclin, terramycin and aureomycin in that order, while chloroquin diphosphate and camoquin gave little indication of therapeutic value.     

The indirect fluorescent antibody test for bovine anaplasmosis

Summary

An indirect fluorescent antibody test was used succesfully for the serodiagnosis of experimental Anaplasma infections in cattle. Specific antibodies were detected three to ten days after anaplasma bodies werd found in the blood, and persistedat least 15 weeks post‐infection.

An American and an African stock of A. marginale were used to prepare antigens, and gave comparable results when tested on sera positive to either of these stocks, as well as to an A. centrale‐like stock from Korea.

There were no cross‐reactions with several Theileria, Babesia, Trypanosoma and Eperythrozoon species.     

Seroepidemiology of bovine anaplasmosis and babesiosis in Venezuela

Summary The serological prevalence of bovine anaplasmosis and babesiosis in the Centro-Occidental region of Venezuela was determined using the indirect fluorescent antibody (IFA) and latex agglutination (LAT) tests.Anaplasma marginale IFA and LAT prevalence rates were 57·7 and 48·6% respectively for cattle of all ages and breeds. The respective prevalence of IFA activity toB. bigemina andB. bovis was 78·2 and 38·8%. The LAT test specific only forBabesia spp. revealed that 61·4% of the animals tested were serologically positive forBabesia parasites.Anaplasma marginale andB. bigemina organisms were detected in peripheral blood smears of 21·1 and 7·5% respectively of cattle surveyed. A longitudinal survey of antibody activity and incidence of parasitaemia forAnaplasma andBabesia infections was conducted in two groups of calves from their birth to seven months of age. The animals generally experienced infections between three and four months of age the period subsequent to decline in colostral antibody levels. Seroepidemiological data are considered in the formulation of proposed vaccination regimens for anaplasmosis and babesiosis.

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Resumen Se determinó la prevalencia serológica de anaplasmosis y babesiosis bovina, en la región central occidental de Venezuela, utilizando la prueba de immunofluorescencia indirecta PIFI) y la aglutinación del latex (PAL). Las ratas de prevalencia PIFI y PAL paraAnaplasma marginale fueron 57·7% y 48·6% respectivamente, en ganado de todas las edades y razas. Las respectivas prevalencias de la actividad de PIFI, pa paraBabesia bigemina yB. bovis fue 78·2% y 38·8%. La prueba PAL, ú únicamente especifica paraBabesia spp. reveló que el 61·4% de los animales analizados fueron serológicamente positivos paraBabesia. Se detectóAnaplasma marginale yB. bigemina en la sangre periférica de 21·1% y 7·5% respectivamente, del ganado analizado. Se llevó a cabo, un reconocimiento longitudinal, de la actividad de los anticuerpos e incidencia de parasitémia, paraAnaplasma yBabesia, en dos grupos de terneros, desde el nacimiento hasta los siete meses de vida. Los animales experimentaron las primeras infecciones, entre los tres y cuatro meses de vida, el periodo con posterioridad a la pérdida de inmunidad materna.

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Résumé La prévalence sérologique de l'ánaplasmose et de la babésiose bovines dans la région centre-ouest du Vénézuela a été déterminée par les méthodes indirectes de l'immunofluorescence (IF) et de l'agglutination au latex (AL). Les taux de prévalence d'Anaplasma marginale d'après les tests IF et AL sont respectivement de 57, 7 p. 100 et de 48,6 p. 100 chez les bovines, quel que soit l'age ou la race. La prévalence respective du test IF vis-à-vis deB. bigemina et deB. bovis est de 78,2 p. 100 et de 38,8 p. 100. Le test de l'agglutination au latex dont la spécificité est limitée au genreBabesia spp a montré que 61,4 p. 100 des animaux testés avaient une sérologie positive vis-à-vis des parasitesBabesia. Anaplasma marginale etB. bigemina ont été décelés dans des frottis de sang périphérique chez 21,1 p. 100 et 7,5 p. 100 respectivement des bovins testés. Un suivi dans le temps de l'activité des anticorps et de l'incidence de la parasitémie vis-à-vis des infections àAnaplasma etBabesia a été pratiqué dans deux groupes de veaux depuis leur naissance jusqu'à l'age de 7 mois. Les animaux contractent généralement l'infection entre l'age de 3 et 4 mois, période qui succède au déclin des taux d'anticorps colostraux. Ces données de séroépidémiologie sont prises en compte dans l'établissement de campagne de vaccination contre l'anaplasmose et la babesiose.

     

Epidemiology of bovine babesiosis and anaplasmosis in Zambia

The serological prevalence of bovine babesiosis and anaplasmosis in the traditional farming sector of six provinces of Zambia was determined using the indirect fluorescent antibody test (IFAT) for babesiosis and the card agglutination test (CAT) for anaplasmosis. Antibodies to Babesia bigemina occurred throughout the country whereas the prevalence of B. bovis followed the distribution of its tick vector Boophilus microplus which is limited to the north-eastern part of the country. Low numbers of B. bovis serologically positive cattle were demonstrated in central and southern Province. Anaplasma spp. occurred throughout Zambia but the overall percentages of positive sera were low ranging between 14.7% and 38.6% using the CAT. Two hundred sera were retested for anaplasmosis using an enzyme-linked immunosorbent assay (ELISA). Sero-prevalence rates were 1.5 to 2.3-fold greater with the ELISA than with the card agglutination test.     

Post-thawing viability of vaccines for bovine babesiosis and anaplasmosis cryopreserved with glycerol

Live frozen vaccines containing Babesia bovis, Babesia bigemina or Anaplasma centrale were prepared using glycerol as cryoprotectant and stored in liquid nitrogen. The viability of the vaccines was tested inoculating calves 1 h (n = 12), 2 h (n = 12), 12 h (n = 6) and 24 h (n = 6) after thawing. Babesia bovis and A. centrale were detected in thin and/or thick blood smears in all vaccinated calves; however, 1 of 12 calves inoculated 1 h after thawing and 3 of 6 calves inoculated 24 h after thawing did not develop a B. bigemina parasitaemia. The longer post-thawing durability of frozen vaccines cryoprotected with glycerol compared with those cryoprotected with dimethyl sulfoxide, presented by other authors, will extend their use under field conditions.     

Epidemiology of bovine anaplasmosis in dairy herds from Costa Rica

Bovine anaplasmosis is endemic and occurs in almost all areas of livestock production of Costa Rica. The aim of this study was to determine the seroprevalence and risk factors of anaplasmosis in dairy farms of Costa Rica by the recombinant truncated MSP-5 (rMSP-5) enzyme-linked immunosorbent assay (ELISA). Serum samples were obtained from 733 cattle from 20 commercial dairy herds of Costa Rica. The overall seroprevalence was 37.2% and herd seroprevalence ranged from 20.0 to 72.0%. The age-specific seroprevalence was 49.3% in young and 33.4% in adult animals. The main risk factors associated with seroprevalence were season of occurrence of clinical cases (rainy season) (OR=22.8), presence of tabanids (OR=9.5) and stable flies (OR=6.2), stable flies control measures (OR=3.2), non-use of ear tattoos (OR=2.8), interval of veterinary visit (≤ 60 days) (OR=2.7), altitude of the farms (<800 masl) (OR=2.6) and age (<2 years) (OR=1.8). The results indicated that exposure of cattle to Anaplasma marginale is common in dairy herds of Costa Rica and endemic instability situation probably is due to inadequate vector control.     

Molecular epidemiology of bovine anaplasmosis in Khyber Pakhtunkhwa,Pakistan

Bovine anaplasmosis is endemic in Pakistan where it reduces livestock productivity and leads to high mortality, especially in young animals. This study was aimed to identify the potential risk factors responsible for the occurrence and spread of anaplasmosis in cattle and buffaloes for the first time in Pakistan. A total of 900 (cattle?=?479, buffalo?=?421) blood samples were collected irrespective of age and sex from three distinct zones of Khyber Pakhtunkhhwa (KP) province of Pakistan. Polymerase chain reaction (PCR) technique was used for the molecular detection of anaplasmosis. Data collected on a piloted questionnaire including 11 predicting variables which were analyzed using R-statistical software, and association between the dependent and independent variables was assessed using univariable analysis. Automated and manual approaches were exercised, producing comparable models. Key risk factors identified in all the approaches included species of the animal, breed of animal, sex of animal, tick infestation status, previous tick history, tick control status, and acaricides used (odds ratio?>?1). The 611 bp DNA fragment specific for 16S rRNA gene of Anaplasma spp. was produced from 165 samples. The samples were confirmed for anaplasmosis through sequencing and BLAST queries. The findings of the current study conclude that by enhancing the protective measures to control the identified risk factors can reduce the spread of anaplasmosis in Pakistan.