Bovine anaplasmosis prevalence in northern Veracruz state, Mexico

In order to learn more about the presence of bovine anaplasmosis in northern Veracruz sate, Mexico, paired blood and serum samples from 368 cattle were subjected to polymerase chain reaction (PCR) and complement-fixation test (CFt). The overall prevalence of Anaplasma marginale by PCR was 69.2% and seroprevalence by CFt 54.6%. Age-specific prevalence was calculated for each test. Sixty-eight percent of animals from 0 to 3 months of age already were infected (PCR-positive), compared to only 42.4% positive by serology. CFt results suggested that presence of antibody increases with age up to 18 to 36 months, decreasing thereafter. Presence of the rickettsia seems to follow the same early pattern but with a new increase in animals 36 months or older. Serology results provided a biased picture of the true prevalence of anaplasmosis. Calculated specificity and sensitivity (63.5% and 68.2%) for CFt using PCR values as true values, appear very low and unreliable. The data generated by DNA-based surveys seem more appropriate to help design and implement control or eradication programs for bovine anaplasmosis.     

墨西哥尤卡坦半岛养蜂业

墨西哥地处北美洲,自然资源丰富,是世界第五大蜂蜜生产国和第六大蜂蜜出口国,近年来其在国际上蜂蜜出口的位置有所下降,1995年墨西哥曾是世界第三大蜂蜜出口国。尽管尤卡坦半岛面积只有墨西哥国土面积的8%,但它包括墨西哥的坎佩切州(Campeche)、金塔纳罗奥州(Quintana Roo)和尤卡坦州(Yucatan)三个州,蜂蜜产量占全国产量的30%~40%。     

Bovine babesiosis in Colombia

Babesiosis is a tick-borne disease of cattle which occurs in many tropical and subtropical areas of the world. Despite the extensive investigations which have been carried out since the discovery of the organism (Babes, 1888) many problems of major importance remain to be solved in Babesia spp. — host complex. In Colombia (South America) the experiments were carried out to identify the existing Babesia spp. by morphologic and immunoserologic methods. The immunoserologic relationship of Babesia spp. were studied by several serologic techniques. Attempts were made to develop a sensitive and practical serologic test for diagnosis of latent Babesia spp. infections. Several groups of intact and splenectomized calves were inoculated with various antigens isolated from Babesia spp. infections and the response to vaccination, premunition and tick-borne challenge were studied. The second part of this investigation was mainly concerned with evaluating the system of chemoprophylaxis against Babesia spp. infections under actual field conditions.     

Bovine babesiosis in the European community

There are apparently three species of bovineBabesia within the European Community-B. divergens,B. major andB. bovis. The former is the principal cause of disease, but lack of information about the other two, particularly about the ability of the tickIxodes ricinus to act as their vector, makes further investigation essential. The potential hazard of indiscriminate movement of cattle within the E.C. is discussed, and a plea is made for the introduction of routine serological screening of cattle before their export.

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Kurzfassung In der Europäischen Gemeinschaft scheint es drei Arten vonRinderbabesia zu geben,B. divergens,B. major undB. bovis. Die erste Art ist die Hauptkrankheitsursache, aber mangelnde Kenntnisse über die anderen beiden, besonders über die Fähigkeit der ZeckeIxodes ricinus als übertrager zu dienen, lässt weitere Untersuchungen wesentlich erscheinen. Die potentiellen Gefahren durch uneingeschränkte Viehbewegungen innerhalb der EG werden erörtert, und es wird für die Einführung routinemässiger serologischer Untersuchungen der Tiere vor ihrer Ausfuhr plädiert.

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Resume Il existe apparemment trois sortes debabésia bovine dans la Communauté Européenne-B. divergens,B. major etB. bovis. La première est la cause principale de la maladie, mais le manque d'informations concernant les deux autres, particulièrement la capacité de la tiqueIxodes ricinus d'agir en tant que vecteur de ces maladies, rend des recherches complémentaires absolument nécessaires. Le danger virtuel que constituent les mouvements désordonnés de bétail à l'intérieur de la Communauté Européenne fait l'objet d'un discussion, et il est préconisé l'analyse systématique du sérum du bétail avant son exportation.

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Riassunto Nella Comunità europea pare esistano tre specie diBabesia bovina cioè-B. divergens,B. major eB. bovis. Principale causa di malattia è la prima, ma la mancanza di sufficienti informazioni sulle altre due, soprattutto riguardo al ruolo della zeccaIxodes ricinus come vettore, richiede lo svolgimento di ulteriori ricerche. I rischi potenziali inerenti al movimento indiscriminato dei bovini nella C.E. sono oggetto di discussione e si suggerisce l'istituzione di regolari controlli sierologici dei bovini prima che gli stessi vengano esportati.

     

Bovine viral diarrhoea virus in beef cattle herds of Yucatan, Mexico: seroprevalence and risk factors

A survey of bovine viral diarrhoea virus (BVDV) infection was carried out from June 2001 to July 2002 in a non-vaccinated beef cattle population from the livestock region of Yucatan, Mexico, to assess seroprevalence and identify risk factors related to seroprevalence. The aim was also to estimate the intra-herd correlation (r_e) and design effect (D) of BVDV seropositivity. Cattle were selected by a two-stage cluster sampling. Blood samples were collected from 560 animals originating from 40 herds. Sera were tested for antibodies against BVDV using an indirect ELISA test. The sensitivity and specificity of the test was 97.9 and 99.7%, respectively. Risk factors regarding the herd and each animal sampled were recorded through a personal interview at the time of blood sampling. Twenty-four of the 40 herds had at least one seropositive animal. The animal true seroprevalence was estimated as 14%. The marginal logistic regression model used to describe the data found a significant (p < 0.05) association of herd size–cow-origin interaction. The interaction was due to a higher risk of seropositivity in the category of herds with ≤100 animals and purchased cows (OR = 1) as compared to herds with ≤100 animals and cows born in the farm (OR = 0.23). Seropositivity between cows purchased and cows born in the farm was similar for herd sizes of 101–196 and >196 animals. The r_e and D values were 0.17 ± 0.05 and 3.16 ± 0.57, respectively.     

Beef breed bulls versus selected dual purpose bulls in producing calves for meat production

The mating of small beef type bulls (Angus, Eringer) to reduce difficulties at first calvings is increasingly applied in Switzerland. In contrast to this, calf producers refuse to use large type beef bulls on their cows because of direct and indirect damages due to increased calving problems. It proved to be an attractive alternative to use specially selected dual purpose bulls tested for ease of calving and high growth rate but low dairy performance, so called M-bulls (Meat bulls), out of the regular AI testing programme for Braunvieh and Simmentals.From 1974 to 1976, Charolais, Limousin and Piemontese bulls were included in the AI testing programme and compared with Braunvieh- and Simmental-M-bulls. Data included progeny from 47 bulls, 7936 calvings, 1137 animals with carcass gains, and 130 dissected carcasses. If calving performance and net gains are considered, the M-bulls compete well with the foreign breeds. If, in addition, the amount of meat in the carcass is taken into account, then Charolais and Piemontese crosses are superior. The problem is one of distributing gains and losses among calf producers, feeders and butchers. It needs specially tested bulls with emphasis on ease of calving out of the specialized beef breeds or sire lines to persuade the dairy farmer to cross his cows.     

Bovine fasciolosis in Tabasco, Mexico

To establish seasonal trends in infection and maturity of Fasciola hepatica in cattle in relation to macroclimatic factors, 2730 condemned livers were examined from March 1989 to February 1992. Livestock came from Jalapa, Tacotalpa and Teapa, all municipalities in Tabasco State. Flukes were collected monthly and separated into three different maturation stages. Mean numbers of flukes collected were determined. The analysis of the maturation stages detected in cattle showed: (a) F. hepatica matured throughout the year at all three sites; (b) the greatest mean fluke's burdens were found in Jalapa and the lowest in Teapa; large parasite populations were significantly higher from February to September than in July and/or August; (c) persistence of mature, gravid F. hepatica indicated that parasite eggs are shed throughout the year; (d) recruitment of F. hepatica occurred throughout the year with two major periods of infection, the first and main period during the dry season (from February to June), and a second minor infection period, during the rainy season (from August to October); (e) a close relationship was observed between the seasonal infection pattern in cattle and the seasonal infection pattern in snails, as well as fluctuations in the snail population according to rainfall and temperature variation.     

Prevalence of fetal resorption in stray dogs in Yucatan, Mexico

OBJECTIVES: To determine the prevalence of fetal resorption in 77 pregnant bitches and its association with the age, size and body condition score of the bitch and to determine the frequency of transuterine migration of embryos. METHODS: The number and position of embryos or fetuses and placental zones were registered postmortem. The prevalence of fetal losses was determined by comparing the number of corpora lutea with the number of embryos or fetuses in each bitch. The prevalence of transuterine migration of embryos was determined by correlating the number of fetuses in each horn and the number of corpora lutea in the ipsilateral ovary. RESULTS: Fetal resorption zones were demonstrated in 42.9 per cent of the bitches. However, pregnancy continued in 84.9 per cent of cases. Of the fetal losses, 25.9 per cent were determined by counting the number of corpora lutea and viable embryos or fetuses. Young bitches tended to have a higher probability of fetal resorption than adult bitches (P<0.06). The presence of fetal resorption zones was not associated with size or body condition. Transuterine migration of embryos had occurred in 15.8 per cent of the bitches. CLINICAL SIGNIFICANCE: This study demonstrated that embryo resorption is a normal event in the bitches, with a higher prevalence than previously thought.     

Prevalence of the Dirofilaria immitis infection in dogs from Merida, Yucatan, Mexico

The aim of the present study was to estimate the prevalence of Dirofilaria immitis infection, and to examine the relationship between host factors (gender, age and breed) and D. immitis infection in dogs. The study was designed as a cross-sectional study. A total of 676 dogs were examined for D. immitis infection. Adult worms (necropsy) and blood samples were collected from all animals for diagnosis of D. immitis. Blood samples were examined using a modified Knott's and thick drop techniques. Fifty-six of 676 dogs were diagnosed infected with D. immitis. The odds of infection were 2.85 times higher in female dogs, compared to male dogs (OR = 2.85, 95% CI = 1.5-5.5, P = 0.01). In addition, the odds of infection were 2.11 times higher in > or =3 years old dogs, compared with younger dogs (OR = 2.11, 95% CI = 1.1-4.2, P = 0.03). This information is important for a better understanding of the epidemiology of D. immitis in dogs in Yucatan, Mexico.     

Prevalence of benzimidazole resistant nematodes in sheep flocks in Yucatan,Mexico

Thirty-eight sheep flocks, located in three municipalities in the Eastern Yucatan, Mexico, were surveyed for gastrointestinal nematodes resistant to benzimidazole (BZD) anthelmintics (AH). On each flock, 30 sheep were randomly distributed into two groups of 15 animals: albendazole group (5mg/kg BW) and untreated control group. Animals were refrained from any food (either browsing/grazing or supplement) for a period of 16 h prior to treatment. Faecal egg counts (FEC) and larval cultures were performed 10 days after anthelmintic treatment. Percentage reduction and 95% confidence intervals were determined. Anthelmintic resistance (AR) was declared when the percentage reduction in FEC was <95% and the 95% confidence interval was <90%. AR was suspected when only one of the two criteria was met. The survey indicated that AR occurred in 15.8% (n=6) (95% confidence interval=+/-11.6%) and was suspected in 23.7% of the farms (n=9) (95% confidence interval=+/-13.3%). Post-treatment larval cultures indicated that Haemonchus was the only resistant genus. The questionnaire survey showed that most farmers (92%) considered their sheep a secondary activity to cattle production. The majority of farmers (97.4%) treat their animals according to visual appreciation of weight. However, most farmers (79%) treat their flocks at very low frequencies (<3 times per year). Drug rotation was performed every 12 months or more by 84.2% of farmers. Anthelmintics used were: macrociclic lactones (47.4%), BZD (39.5%), levamisol (10.5%) and 1 farmer used closantel.     

Dual purpose cattle production in Mexico

Cattle production is one of the most important livestock activities in the rural areas of Mexico, with most of the national territory dedicated to it, in addition to the use of the most agricultural supplies and forages resources, as well as agricultural and agro-industrial by-products. Mexico is placed among the ten first meat and milk producer countries worldwide, being the Mexican tropical zone one of the main suppliers of such products. One of the main milk sources is the dual purpose cattle, such systems can be described as those that produce milk (daily milking) and meat (calf after weaning), on every productive cycle. They are mainly located in developing regions and characterized by using low-technology and in poor environments, consequently productive levels are considered low. Milk is destined for self-consumption or for sale at local markets and calf after weaning is sold at local feedlots or for export. Regarding to the little information available about the dual purpose systems, the present work is intended to discuss the main characteristics of cattle production in dual purpose systems in Mexico.     

Bovine babesiosis (Babesia bovis infection) in Zambia

Two cases of Babesia bovis, a parasite associated with the tick Boophilus microplus, are reported for the first time from the central part of Zambia. It is concluded that infected B. microplus ticks are occasionally introduced into central Zambia by tick-infested cattle from the north-eastern part of the country where B. bovis is endemic. The spread of B. microplus in Southern Africa in a westward direction is discussed and related to the epidemiology of bovine babesiosis in Zambia.     

Bovine babesiosis (Babesia bovis infection) in Zambia

Summary

Two cases of Babesia bovis, a parasite associated with the tick Boophilus microplus, are reported for the first time from the central part of Zambia. It is concluded that infected B. microplus ticks are occasionally introduced into central Zambia by tick‐infested cattle from the north‐eastern part of the country where B. bovis is endemic. The spread of B. microplus in Southern Africa in a westward direction is discussed and related to the epidemiology of bovine babesiosis in Zambia.     

Risk factors for Aujeszky's disease in pig herds and detection of field virus antibodies in fattening pigs in the state of Yucatan, Mexico

Two epidemiological studies were conducted from August 1997 to May 1998: a case-control study to identify herd level risk factors for antibodies to Aujeszky's disease virus (ADV) in sows in the state of Yucatan, Mexico and a cross-sectional study to determine the prevalence of antibodies against ADV in fattening pigs. In the case-control study, data on herd management and biosecurity were obtained from all the 27 ADV known field-virus-seropositive farms (cases) and 62 randomly selected seronegative farms (controls) by questionnaire. Breeding animals of these seropositive farms had received a gE-deletion vaccine. In the cross-sectional study, 26 farrow-to-finish farms of the 27 seropositive farms were used and blood samples taken from 60 fattening pigs per herd (15 pigs for each stage of production). Serum samples were analyzed by the screening-ELISA and gE-ELISA tests. In the case-control study, three of the 15 risk factors were significant. Odds ratios for distance to the nearest farm (< or = 2.5km), not sampling for the detection of ADV and herds with origin of breeding animals within the state were 9.5, 18.1 and 8.7. In the cross-sectional study, 11 (42.3%) of the 26 sampled farms were seropositive to vaccine antibodies. None of the piglets were positive to antibodies against field virus risk--suggesting that the strategy of vaccinating only the breeding animals reduced the ADV infection of the piglets.     

Rabies in the state of morelos,Mexico

Summary Rabies incidence is high in the State of Morelos, Mexico. The present study is based on the data obtained from relevant Government institutions. The results from 1980 to 1990 show an average of 3·3 human, and from 1985 to 1990 a total of 3,173 animal rabies positive reports. It was concluded that the anti-rabies programme in Mexico, particularly in the State of Morelos, has not produced adequate results.

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Rabia En El Estado De Morelos, Mexico

Resumen La rabia tiene una alta incidencia en el estado de Morelos, México. El presente estudio está basado en datos obtenidos de instituciones del Gobierno. Los datos de 1980 a 1990 indican una media anual de 3·3 casos de rabia en personas y los datos de 1985 a 1990 muestran un total de 3173 casos de rabia en animales. Se concluyó que el programa de control de rabia en Mexico, particularmente en el estado de Morelos, no ha dado resultados satisfactorios.

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La Rage Dans L'etat De Moralos, Au Mexique

Résumé L'incidence de la rage est élevée dans l'Etat de Morelos, en Mexique. L'étude est basée sur des données obtenues d'institutions gouvernementales appropriées. De 1980 à 1990, on a noté une moyenne de 3,3 cas humains et de 1985 à 1990 un total de 3173 cas de rage animale. On en conclut que le programme antiabique en Mexique, en particulier dans l'Etat de Morelos, n'a pas produit de résultats satisfaisants.

     

Bovine papular stomatitis, first report of the disease in Mexico

In a herd of 120 two to eight months old calves kept at a Mexican Government experimental station in Ajuchitlan, Querétaro, weight loss and ptialism were observed. Upon a clinical examination, it was found that 31 (25.8%) of the animals disclosed papules in the oral and perioral regions. Biopsies from the affected tissues were studied with the light and electron microscopes. Serological studies and isolation of the virus were also carried out. A Pox virus was identified (240 x 100 x 150 +/- 7% nm) with the electron microscope. Dermatophilus sp. was occasionally observed. Bovine kidney monolayers, inoculated with affected bovine tissues demonstrated cytopathic effect up to the 4th serial passage. Inoculation with cell cultured infectious material in the oral submucosa (cell lysate) produced typical lesions of BPS on a heifer. Infectious tissues from this experimentally inoculated animal produced cytopathic effect in tissue cultured cells after 24 hours, and this last material was infectious for a second young heifer. Virus-neutralization tests, using an hyperimmune serum, disclosed a neutralization index of 1.5 logarithms. It was concluded that bovine papular stomatitis virus was the etiological agent.     

Bovine lymphosarcoma in twin calves.

Lymphosarcoma in twin female calves, apparently the first to be observed in Canada, is reported here. Peripheral blood and cultured mononuclear cells of one of the calves showed aneuploidy of the chromosomes. No hematological or serological evidence of bovine leukemia virus infection was observed in the other members of the herd. Bovine leukemia virus infection of the leukemic cells could not be detected by electron microscopy or by tissue culture procedures. There is a need to clarify the relationship of the calf form of the disease to the adult form of enzootic bovine leukosis.     

Ehrlichia canis in dogs in Yucatan, Mexico: seroprevalence, prevalence of infection and associated factors

The aim of this study was to determine the prevalence of infection, seroprevalence, and factors associated with antibody response to Ehrlichia canis in dogs of Yucatan, Mexico. The study was carried out in four veterinary clinics located in Merida, the capital city of Yucatan, Mexico. Blood samples were obtained from a total of 120 dogs, and each animal was physically examined to determine age and sex, as well as to record any clinical signs of platelet-related bleeding. Blood samples were analyzed for antibodies to E. canis using an ELISA test, and thrombocyte counts were calculated. Blood smears were prepared to detect typical morulae in leukocytes. The prevalence of infection, seroprevalence and associated factors were calculated. A primary screening was performed using 2 x K contingency tables of exposure variables. All variables with P< or =0.20 were analyzed by a logistic-binomial regression. Fifty-three (44.1%) of the 120 dogs were found to be seropositive to E. canis. In six dogs (5.0%) typical morulae of E. canis were observed in monocytes. These six cases were positive for antibodies and were thrombocytopenic. The following factors associated with seropositive animals were: platelet-related bleeding (Yes: OR=10.26, CI=2.50-42.16, P=0.001), thrombocytopenia (Yes: OR=18.91, CI=4.47-80.03, P=0.000) and age (2-4 years: OR=6.77, CI=1.76-25.97, P=0.005; >4 years: OR=4.24, CI=1.04-17.21, P=0.043).