Epidemiological investigations of outbreaks of bovine ephemeral fever in Israel

In two epidemics of bovine ephemeral fever (BEF) in Israel, one in 1990 and one in 1999, the virus was probably carried by vectors transported by air currents across the Rift Valley and through the Red Sea trough. The disease broke out under optimal ecological conditions among vulnerable cattle populations and spread rapidly; it developed in the spring and summer and ended soon after the daily average ambient temperature fell below 16 degrees C in late autumn. The proportion of herds affected reached 78.4 and 97.7 per cent in 1990 and 1999, respectively. The highest rates of incidence, morbidity and mortality were recorded in dairy cattle herds in the Jordan Valley, the initial focus of the outbreaks, with a morbidity of 20 and 38.6 per cent in 1990 and 1999, respectively, and mortality among the affected animals of 2 and 8.6 per cent in 1990 and 1999, respectively. In 1991, the disease recurred sporadically in the central and southern regions of Israel in only three herds, but in 2000 the disease returned on an epidemic scale, and 85 per cent of herds were affected, with morbidity and mortality rates of 4-3 and 0-3 per cent, respectively. In the 1999 epidemic, the morbidity rate decreased from 38-6 per cent on average in the Jordan Valley to 12.8 per cent in the inner valleys and 5.3 per cent on the Mediterranean coastal plain, but the mortality rate increased from 8-6 per cent in the Jordan Valley to 14-3 per cent in the inner valleys, and to 28 per cent on the Mediterranean coastal plain, where the outbreak declined. An average of 2-7 per cent of the animals experienced a second attack of the disease two to six weeks later. The epidemic in 2000 was milder and shorter than that in 1999. All the cattle affected in both outbreaks were more than three months old. The vector(s) is not known for certain but the available evidence indicates that mosquitoes, and not Culicoides species, are the natural vectors of BEF virus in Israel.     

Eradication of Chorioptes bovis mange in a dairy herd with turn-out to graze by Eprinex Pour-On

The possibility to control or even eradicate chorioptes manage by a single herd treatment with EPRINEX Pour-On (dosage: 0.5 mg Eprinomection/kg bodyweight) during pasture season was investigated in a dairy herd of 320 dairy cows. A further aim of the study was to evaluate whether such mid-summer treatment with EPRINEX Pour-On due to its endo-ectocide action would at the same time also result in a metaphylaxis of gastro-intestinal and lung worms and in a reduction of fly infestation. Due to clinical symptoms manage prevalence in the herd prior to treatment was 11 percent. After treatment, clinical symptoms disappeared within 2 months completely and did not re-occur during the subsequent housing period. Chorioptes mites during the entire trial period no longer were detected. The final clinical and parasitological investigation shortly before turn-out the next year (April 1999) demonstrated chorioptes mange to be eradicated clinically and parasitologically. Due to the mid-summer treatment infestation with gastrointestinal helminths also was eliminated and clinical symptoms of helminth infestations during the pasture season no longer were observed. However, at housing in November, low numbers of eggs of gastrointestinal nematodes were detected in 6% of dairy cows, 32% of second-season and 63% of first-season heifers, respectively. Milk yield per cow and day on average increased by 1 litre after treatment with EPRINEX Pour-On. This increase in production is likely a result of the reduction in total parasite burden of lactating cows.     

Epidemiological studies of sarcoptic mange in Tanzanian pig herds

Summary An epidemiological survey of sarcoptic mange in 32 herds with a total herd size of 2,021 pigs was conducted in three representative climatic zones in Tanzania. The disease was present in all zones in varying prevalences. The overall prevalences were 52% and 21% when determined on the basis of clinical examination and mite isolation respectively and 91% of the herds were shown to be harbouring the disease.

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Estudios Epidemiologicos De Sarna Sarcoptica En Piaras En Tanzania

Resumen Se llevó a cabo un estudio epidemiológico de sarna sarcóptica en 2021 cerdos en piaras de tres zonas climáticas representativas de Tanzania. La enfermedad se detectó en todas las zonas en varios niveles de prevalencia. La prevalencia general fue de 52% y 21% cuando ésta se determinó sobre la base de exámenes clinicos y aislamiento del ácaro, respectivamente; 91% de las piaras estaban infectadas.

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Etude Epidemiologique De La Gale Sarcoptique Sur Des Troupeaux Porcins En Tanzanie

Résumé Une enquête épidémiologique sur la gale sarcoptique portant sur 32 troupeaux totalisant 2021 porcs a été conduite dans trois zones représentatives de Tanzanie du point de vue climatologique. La maladie a été rencontrée partout à des degrés divers. La prévalence totale des sujets a été de 52 p. 100 et de 21 p. 100 selon qu'elle était déterminée à partir d'un examen clinique ou de l'isolement des parasites respectivement. Enfin, la maladie a été décelée sur 91 p. 100 des troupeaux examinés.

     

Productivity effects of bovine mange and control with ivermectin

A randomised block design study was conducted to evaluate the effects of mange on cattle. Twenty-four Simmentaler Fleckvieh bulls were formed into eight replicates of three bulls based on Day -56 body weight (288-414 kg). Within replicates bulls were randomly allocated to groups G1: uninfested control, G2: infested control or G3: infested, treated with 0.2mg ivermectin/kg (1% ivermectin injection; IVOMEC, Merial) on Day 0. The G2 and G3 bulls were infested with Sarcoptes/Chorioptes mites on Days -56 and -49. Feed consumption was recorded daily throughout the study (Days -56 to 56). Body weights were measured and serum samples collected. Mites were counted at bi-weekly intervals from Day -14 on. The carcasses of the bulls and the leather produced from their hides were evaluated. Differences between variables were declared significant if P相似文献   

Epidemiological approaches to safety investigations

This paper considers the different approaches to post-authorisation safety monitoring of veterinary medicinal products that is essential to ensure confidence in their safety. Most safety testing is undertaken prior to granting of a marketing authorisation and is generally on a small scale. Field trials are usually much larger, but still involve relatively low numbers of animals compared to the number to which authorised products are administered. Safety testing is generally aimed at detecting common events; the numbers of animals used in the tests are too small for detection of all but the most common reactions. The efficiency of the tests depends on the frequency and severity of the adverse reaction and the ability to associate the adverse event with the product. The latter is affected by the period of time between administration and the event, as well as by its underlying frequency. Adverse reaction surveillance is critical in monitoring the safety of a marketed product. Most is entirely passive and so reporting rates are likely to underestimate true incidence. It is relatively efficient for rare, serious adverse effects and for those with a low underlying frequency in the population, but it is less useful when there is long period between administration and the event, or where the event has a relatively high underlying frequency. Greater emphasis should be placed on active surveillance after production registration. Detailed epidemiological investigations, including cohort, case control and cross-sectional designs, offer the only approaches that provide more information on the association between a product and events that have a high underlying frequency in the population or where there is a long period between administration and the adverse event. The relative merits of different approaches are discussed, with particular reference to our recently published study of the temporal association between canine vaccination and non-specific signs of ill health and plans to undertake studies of associations with feline injection site sarcoma. Emphasis is placed on the need for clearly stated hypotheses and the consideration of equivalence, rather than significance testing when considering safety studies.     

Epidemiological studies of bovine spumavirus

Bovine spumavirus (BSV) infection is shown to be endemic in some herds in north Queensland. The virus was readily isolated from leukocytes of the majority of mature cattle which were BSV antibody positive (BSV reactors) in the agar gel precipitin test (AGPT). Calves born to dams which were BSV reactors showed no BSV antibody or circulatory leucocyte-associated BSV (CLAB) at birth, but became BSV reactors following ingestion of colostrum, and maintained such evidence of passive immunity until 3–5 months of age. Experimental infection of dams with BSV at 5–7 months of gestation did not cause foetal infection.In groups of young animals at pasture, segregated by age and sex, no evidence of BSV infection occurred, following loss of passive immunity, until 18–24 months of age. At this time, occasional members of some groups (both male and female) became BSV reactors and showed CLAB. At ≈24 months old, following mixing in groups with older cows, and single-sire mating, 34% of heifers became BSV reactors within 10 weeks. A herd survey indicated 85% of 2–3-year-old cows to be BSV reactors; thereafter, the percentage of reactors declined gradually with increasing age.Using BSV grown in cell culture, transmission of infection by throat spray was the most successful route, 7 of 7 (100%) of susceptible cattle becoming BSV reactors within 8 weeks of spraying. Using the intravenous route, only 2 of 5 (40%) susceptible cattle became BSV reactors, and swabbing of cell culture virus into the prepuce or vagina did not result in infection of 4 BSV-susceptible animals. Virus could not be detected by in vitro or in vivo procedures in throat swabs taken from BSV reactors which were CLAB positive.In discussion, epidemiological data are used to support postulates that the spread of BSV infection is associated with intimate contact between individuals, and that the vehicle of infection is saliva. Only saliva from BSV-infected cattle which have no specific antibody is considered to be infectious. Such animals are either those incubating BSV infection before development of an immune response or, more logically to the authors, animals which are BSV tolerant, possibly owing to in utero infection.     

Epidemiological study of enzootic bovine leukosis in Brazil

Tropical Animal Health and Production -     

Epidemiological investigations of the 2001 foot-and-mouth disease outbreak in Argentina

A total of 2126 herds, an attack rate of 0.82 per cent, were affected during an epidemic of foot-and-mouth disease in Argentina in 2001. The spatial and temporal distribution of the epidemic was investigated using nearest-neighbour and spatial scan tests and by estimating the frequency distributions of the times to intervention, and distances and times between outbreaks. The outbreaks were clustered and associated significantly (P<0.01) with herd density; 94 per cent were located in the Pampeana region, where the cattle population is concentrated, which had an attack rate of 1.4 per cent. The clustering results suggested that the virus had spread locally between outbreaks. Most of the outbreaks were separated by one day and the maximum distance between outbreaks was almost 2000 km, indicating that the infection spread rapidly over large distances. The index outbreak was detected more than 15 days after the primary outbreak, and restrictions on the movement of cattle were probably not enforced until about one month after infection occurred. As in other major epidemics, the period between the first outbreaks and the effective application of control strategies was probably crucial in determining the progress of the epidemic.     

Immunopathological investigations on bovine digital epidermitis

Paraffin-embedded fragments of bovine digital skin lesions were sectioned and stained with Warthin-Starry, haematoxylin and eosin, Grocott's methenamine silver and immunohistochemical techniques. Microorganisms observed in the silver-stained sections were classified into four major morphological groups. Spirochaetes were the most prevalent organisms, but bacillary and coccoid elements were also present in most sections. Immunohistochemical probing demonstrated that approximately 80 per cent, 46 per cent and 41 per cent of the digital and interdigital dermatitis sections stained positively with polyclonal antisera to Treponema pallidum, Campylobacter jejuni and Fusobacterium necrophorum, respectively. An unidentified branching filamentous organism (presumed to be an actinomycete) was consistently present in the sections of samples from mild interdigital lesions.     

云南省红河州猪繁殖障碍综合征的流行病学调查

针对云南省红河州猪繁殖障碍综合征严重危害养猪业的情况，对全州12个县（市）21个种猪场982户农户的4 329头繁殖母猪和种公猪进行了流行病学调查。结果表明，猪繁殖障碍综合征发病率在种公猪为23．6％，妊娠母猪为40．69%，初生仔猪死亡率为18．6％；在死亡仔猪中，流产占10．1％，死胎占54．5％，弱仔占32．5％，畸形占2．9％。初步查清了引起红河州猪繁殖障碍综合征的主要病原有细小病毒（PPV）、伪狂犬病毒（PRV）、衣原体（Chlamydia）、乙型脑炎病毒（JEV）、刚地弓形虫（TG）、猪生殖与呼吸综合征病毒（PRRSV）、圆环病毒2型（PCV2）、布鲁氏菌（Bruc）和猪瘟病毒（CSFV）等9种，其中CSFV的带毒率为1．19／6，其他病原的血清抗体阳性率分别为PPV27．7％，PRV24．6％，衣原体22．8％，JEV13．6％，TG12．0％，PRRSV11.5％，PCV27．2％，Bruc4．6％，总阳性率达75．4％，其中单一病原抗体阳性率为39．6％，两种和两种以上病原抗体阳性率为35．6%。     

北京地区犬猫弓形虫病流行病学调查

为初步调查北京地区犬猫弓形虫感染的流病学特征,用酶联免疫吸附试验(ELISA)方法检测2010年5月至2011年4月采集的家养犬猫、流浪猫血清样本.其中,家养犬血清样本1876份,家养猫血清样本561份,检测发现,家养犬动物弓形虫IgG抗体阳性率24.9％;家养猫弓形虫IgG阳性率21.2％;同时检测流浪猫样本201份,阳性率30.3％.家养犬弓形虫血清抗体阳性率不同季节间差异显著(P＜0.05),夏季最高,为30.0％,家养猫弓形虫血清抗体阳性率不同季节间无显著差异(P＞0.05).不同性别犬猫弓形虫血清抗体阳性率无显著差异(P＞0.05).随着年龄增长,犬猫弓形虫抗体阳性率均有明显增长.对25例弓形虫抗体阳性家养犬病例和37例弓形虫抗体阳性家养猫病例进行了回访调查,结果发现,该62例动物主人的弓形虫检测结果均为阴性.     

广西牛片形吸虫流行情况调查

为了解广西牛片形吸虫的流行情况,本文通过胆囊检查法对广西黄牛和水牛片形吸虫的流行情况进行了调查,结果表明广西水牛片形吸虫的感染纯阳性率为53.94%,黄牛阳性率为50.47%,水牛和黄牛分别有31.50%和9.35%为疑似感染,阴性分别只有14.56%和40.19%,说明广西牛片形吸虫感染情况非常严重.     

Epidemiological investigations on Trichinella infections in farmed fur animals of Estonia

Farming of fur animals represents an important income in Estonia. Even though Trichinella worms does not induce a symptomatic disease in carnivores, the carcasses of skinned animals can increase the biomass of the parasite in the environment, if they are not properly destroyed. The aim of the present survey was to study the prevalence of Trichinella worms in farmed fur animals of Estonia. Of 281 muscle samples from blue foxes (Alopex lagopus), silver foxes (Vulpes vulpes fulva), minks (Mustela vison) and raccoon dogs (Nyctereutes procyonoides), which were collected in eight farms, Trichinella larvae have been detected in 21 animals (8%) from two farms by HCl-pepsin digestion. The highest number of larvae per gram of muscle was found in the front limb muscles. Larvae of the 21 isolates have been identified as Trichinella britovi or Trichinella nativa by a multiplex-PCR analysis.     

Concentration of ivermectin in bovine serum and its effect on the fecundity of psoroptic mange mites

The concentration-time profile of ivermectin in serum was determined for 3 Hereford heifers. The mean maximum serum concentration, 29 ng of ivermectin/ml, was obtained 48 hours after single subcutaneous injection of 200 micrograms/kg of body weight. The fecundity of mites placed on 9 treated animals at 5, 9, 12, 15, 18, and 21 days after injection was reduced by 96% to 99%. At 24 days after treatment, when serum concentration had decreased to about 2 ng/ml, the capability of mites to produce eggs increased to 50% of mites from nontreated calves. At 27 and 30 days after the drug was injected, egg production by mites on treated calves was equivalent to that of mites on nontreated calves. The reduced fecundity resulted from an almost complete cessation of oviposition by females after only a 1-day exposure to ivermectin-treated calves.     

Epizootiological investigations of canine distemper virus in free-ranging carnivores from Germany

Canine distemper virus (CDV) infects a broad range of carnivores. To assess whether wild carnivores may play a role in the epidemiology of CDV in domestic dogs in Germany, the seroprevalence of CDV was determined. In sera from red foxes (30 of 591 (5%)) and stone martens (2 of 10 (20%)) antiviral antibodies were detected using a neutralization assay, whereas sera of raccoons, two mink, one pine marten and one raccoon dog were negative. In foxes, there was a significantly higher prevalence in urban and suburban compared to rural regions. When testing lung and spleen tissue samples (fox, badger, stone marten, polecat, raccoon dog) 13 of 253 (5.1%) foxes, 2 of 13 (15.4%) stone martens and 2 of 6 (33%) badgers were virus positive using RT-PCR. Phylogenetic analysis based on partial sequences of the F gene revealed a distinct relatedness to canine CDV isolates. Together, the data support the concept of transmission of CDV between domestic dogs and wild carnivores.     

Epidemiological investigations into the sources of Salmonella contamination of pork

This study was conducted to elucidate which phases of the pork production chain contribute to the Salmonella contamination on pork after slaughter. During 7 sampling days, samples were collected of randomly selected slaughter pigs and of pigs from selected Salmonella-infected and Salmonella-free herds, trucks, lairages, and slaughterlines, in two slaughterhouses. Salmonella genotypes, present on pork after slaughter, were compared with Salmonella types, present on the farm, in the truck, in the lairage, on slaughter equipment, and in pigs from other herds. Results showed that the slaughterline was the most important source of Salmonella contamination of carcasses. The farm was the most important source of contamination of livers, tongues, rectal samples and mesenterial lymphnodes, for pigs originating from sero-positive herds. The lairage was the most important contamination source for pigs originating from sero-negative herds, for all samples, except carcasses. It is recommended to avoid each direct or indirect contact between different herds along the whole pork production chain, especially between Salmonella-infected and Salmonella-free herds.     

Epidemiological study on clinical bovine dermatophilosis in northern Ethiopia

A total of 5586 indigenous and cross breed cattle were examined for clinical dermatophilosis, and 292 (5.22%) were positive. In indigenous cattle, statistically discernible (p < 0.05) difference was recorded between the prevalence in wet (5.5%) and dry (4.0%) seasons. During both seasons, infestation with A. Variegatum significantly (p < 0.05, chi 2 = 59.9) influenced clinical dermatophilosis. A. variegatum-infested cattle were at 7x higher risk (OR, Odds Ratio = 6.8) of acquiring the disease than non-infested ones. Logistic regression analysis of the overall prevalence showed a significant difference (p < 0.05) between prevalence in indigenous and cross breeds; the crossbreeds being at about 3x higher risk (OR = 2.68). Improved management reduced the prevalence in cross breeds from 15.1% in dry to 8.6% in wet season suggesting the significance of management in the epidemiology of dermatophilosis. The disease occurrence was also significantly (p < 0.05, chi 2 = 133.05) affected by agro-climatic (altitude) variation suggesting the impact of rainfall, humidity, vegetation and vector population that varied with altitude. Age and gender had no influence (p > 0.05) on the disease. Our result showed that season of the year, breed, management, infestation with A. variegatum and agro climatic difference are important risk factors influencing the disease pattern in the region. A tick control strategy and a better and adequate management particularly when keeping cross breeds are recommended.