Comparative Evaluation of a Field-based Dot-ELISA Kit with Three Other Serological Tests for the Detection of Brucella Antibodies in Goats

A dot-ELISA (d-ELISA) test was evaluated and compared with the serum agglutination test (SAT), micro-complement fixation test (CFT) and a plate-ELISA (p-ELISA) for field use in screening herds of goats against brucellosis. During the standardization of the dot-ELISA kit on 1732 caprine serum samples, 1571 samples out of 1666 were found to be negative in d-ELISA, SAT and micro-CFT, while 59 were positive in different combinations. Of a further 66 serum samples, 34 were negative and 31 were positive in different combinations in d-ELISA, SAT, micro-CFT and p-ELISA. A total of 1584 goats belonging to different herds were then screened for brucellosis. Of the 694 serum samples screened in the first batch using d-ELISA, a positive reaction was observed in 26 cases. Further screening of these cases revealed 13 and 21 goats as positive reactors in SAT and CFT, respectively. In a second batch of 890 goats there were 109 positive reactors in d-ELISA. Among these 109 goats, 34, 40 and 80 goats were positive reactors in SAT, CFT and p-ELISA, respectively. The results of d-ELISA correlated well with those of p-ELISA. Dot-ELISA was found to be a more suitable and rapid test for screening large numbers of goats in the field.     

Re-emergence of Pigeon Fever (Corynebacterium pseudotuberculosis) Infection in Texas Horses: Epidemiologic Investigation of Laboratory-Diagnosed Cases

In recent years, Texas has seen a dramatic increase in the number of clinical cases of Corynebacterium pseudotuberculosis (pigeon fever) infection in horses. Equine pigeon fever cases at Texas Veterinary Medical Diagnostic Laboratories (TVMDL) were analyzed with the objectives of investigating the spatiotemporal distribution and seasonal and annual trends of pigeon fever infection in horses in Texas between 2005 and 2011 and identifying high-risk areas and create a risk map for pigeon fever in horses in Texas. The study population consisted of horses culture-positive for C. pseudotuberculosis between January 1, 2005, and December 31, 2011 at TVMDL. The Poisson model of scan statistics was fitted to identify disease clusters. Empirical Bayesian smoothing was performed with the crude incidence estimates, followed by the geostatistical method of kriging to delineate high-risk areas. Cases increased 10-fold between 2005 and 2011. The annual cumulative incidence ranged from 9.3 to 99.5 per 100,000 horses at risk. Two seasonal peaks in the number of cases were observed in June and in December. Scan statistics identified a primary cluster in central Texas in 2011 (P < .0001 and relative risk of 9.2). Isopleth risk mapping also delineated a high-risk area in central Texas. High-risk areas were also detected in the panhandle and northern Texas. The epidemiological investigation supported anecdotal reports that pigeon fever is re-emerging in the Texas horse population. This study provides a baseline for future investigations of pigeon fever in the Texas horse population and serves as a reference for the disease distribution for veterinarians and horse owners.     

A Serological Investigation into Contagious Caprine Pleuropneumonia (CCPP) in Ethiopia

For a comparison of serological tests for CCPP, sera from 767 goats were examined. They were subjected to three tests: complement fixation test (CFT) with Mycoplasma capricolum subspecies capripneumoniae antigen; blocking ELISA (B-ELISA) with Mycoplasma capricolum subspecies capripneumoniae antigen; and CFT with Mycoplasma mycoides subspecies mycoides small colony type antigen. Antibodies were detected by these three tests in 23%, 2% and 12%, respectively, of sera from districts in which CCPP had not been reported, and in 60%, 83% and 87%, respectively, in sera from areas in which CCPP had been reported. The specificity of the tests is discussed. The use of the B-ELISA test for the diagnosis and for epidemiological studies of CCPP is strongly recommended.     

Clostridium Infection (Jisizheng) in Yaks in Qinghai,China

Since the mid-1980s, outbreaks of a disease characterized by a sudden onset, acute deaths and extensive haemorrhages in the viscera and digestive tract of yaks have been prevalent in Qilian, Qinghai, China. The disease is known as jisizheng by local people. Virulent Clostridium perfringens type A and Clostridium haemolytica were isolated from yaks that had died of jisizheng. In 1996 and 1997, yaks were immunized with a polyvalent inactivated vaccine against C. perfringens and with an inactivated vaccine against C. haemolyticum, and this prevented the occurrence of jisizheng.     

Detection of Antibodies Against Peste des Petits Ruminants Virus in Sera of Cattle,Camels, Sheep and Goats in Sudan

Detection of antibodies against peste des petits ruminants virus in sera of cattle, camels, sheep and goats in Sudan.     

Studies on the Epidemiology of Tropical Theileriosis (Theileria annulata Infection) in Cattle in Central Anatolia,Turkey

An epidemiological survey for Theileria annulata infection was conducted in 12 selected villages around Ankara in Central Anatolia, Turkey, during the period April 1990 to January 1993. During the survey, 198 cattle of 30 local breeds, 84 Holstein-Friesian×local breeds and 84 Holstein-Friesian breed were examined for antibodies to T. annulata and the presence of the vector ticks. Four species of Hyalomma ticks were identified: Hyalomma anatolicum anatolicum, Hyalomma anatolicum excavtum, Hyalomma detritum and Hyalomma marginatum marginatum. Salivary gland staining indicated that infected adult ticks of all four species were present and, therefore, were implicated in the transmission of tropical theileriosis in the field. Generally, the Hyalomma infestation rate was low, with the heaviest infestations occurring on the older animals. Young adults and calves had very low infestation rates. Most ticks seen on cattle were adults, very few nymphs were found. The blood smear and serological examination of the 198 cattle conducted in March, before the start of the first disease season, showed that the prevalence of piroplasmosis was 11.1% (22 out of 198) and the seroprevalence of T. annulata was 10.6% (21 out of 198). Forty-three animals were then excluded from the study because they were seropositive and/or harboured piroplasms. Ninety-two seronegative animals showed piroplasmosis (92 out of 155) and 34 seronegative animals became seropositive for T. annulata (34 out of 155) during the three disease seasons. One animal became clinically ill with tropical theileriosis and required treatment. The incidence of cattle showing piroplasmosis and disease in the total study sample was 50.7% and 0.5% per disease season, respectively. The seroconversion rate of new infection with T. annulata in the total study was 14.3% per animal season. The number of cattle showing piroplasmosis was much greater than the number of seropositive cattle, which may indicate the presence of another species of Theileria. The two different management systems encountered in the study were considered to have influenced the tick infestation levels.     

Experimental Encephalitozoonosis in the Blue Fox: Clinical,Serological and Pathological Examinations of Vixens after Oral and Intrauterine Inoculation

Inoculations of vixens with Encephalitozoon cuniculi (E. cuniculi), performed orally, either before or in the gestation period, or directly into the uterus at oestrus, induced clinical encephalitozoonosis in the offspring. The infection of the vixens, indicated by a general E. cuniculi antibody response, appeared to run a subclinical course. Endometritis was detected in some of the vixens when examined at the end of the trial. A temporary increase of total protein, albumin and globulin in the inoculated vixens compared to the controls was detected in the final 2 weeks of the gestation, concomitantly with the rise in humoral E. cuniculi antibody titres. The antibody levels appeared significantly higher in the group of vixens inoculated directly into the uterus than in the orally inoculated groups. Vixens exposed to the parasite seemed to possess a certain degree of acquired resistance to re-infection with the parasite when exposed in the following breeding season.     

Evaluation of Diagnostic Tests for <Emphasis Type="Italic">Trypanosoma evansi</Emphasis> in Experimentally Infected Pigs and Subsequent Use in Field Surveys in North Vietnam and Thailand

This study is concerned with the evaluation of established diagnostic tests for diagnosis of Trypanosoma evansi in pigs. The immune trypanolysis test (TL), card agglutination test (CATT), latex agglutination test (LATEX), enzyme-linked immunosorbent assay (ELISA), microhaematocrit centrifugation technique (MHCT) and mouse inoculation (MI) tests were initially evaluated in experimentally infected fattening pigs. All infected pigs were confirmed parasitologically positive with both MHCT and MI. Results of the serological assays indicated that the TL could be a reference test for the presence of RoTat 1.2 antibodies in pigs. The results of the CATT and LATEX were inconsistent with the TL while the ELISA results correlated with the TL results. The four serological assays were subsequently used in two field surveys in Vietnam and Thailand. Results of the two agglutination assays (CATT and LATEX) were not consistent and did not correlate with TL results. The ELISA at percentage positivity of 22 appeared to have good ability to discriminate between seropositive and seronegative animals. Of the 437 samples collected at smallholder pig premises in northern Vietnam, no positive pigs were detected with the TL test. In Thailand, 77 samples were collected from five farrowing farms with a history of surra. Two parasitologically positive sows were found and on each farm seropositive sows were detected.     

Efficacy of Sarafloxacin in Broilers after Experimental Infection with Escherichia coli

Infections of chickens with Escherichia coli serotypeO78 can be treated with the antibiotic sarafloxacin. Three experiments were conducted on the administration of this drug to chickens that had been experimentally infected with E. coli. The birds were monitored for 10 days after infection for their average daily gain (ADG) and feed conversion ratio (FCR), and the post-mortem pathology was assessed. In the first experiment, sarafloxacin (20 mg/L, equivalent to 5 mg/kg live weight per day), given in the drinking water for 3 days after infection, led to a reduction in the mortality from 75% to 27%, but the ADG of the treated birds was still less than that of the uninfected controls. In the second experiment, when the sarafloxacin was administered at the same dose in the water but over only 2 h, there was also a considerable reduction in mortality, and the ADG and the FCR also improved significantly. In the third experiment, the dose dependence of the drug was tested. The birds were given 5 and 10 mg/kg per day sarafloxacin in each group, starting within 2 h after infection. This rapid administration of the drug completely prevented mortality, while the ADG and FCR were similar to those of the uninfected controls.     

The validity of some haematological and elisa methods for the diagnosis of canine heartworm disease

Examinations for heartworm (Dirofilaria immitis) were performed on 175 impounded dogs from a hyperendemic area of the Po Valley (Italy). Each blood sample was used wiht five haematological diagnostic methods (filtration, direct smear, modified Knott, clotted blood and capillary tube) and three commercial ELISA kits (PetChek, Diasystems, Uni-Tec). The results were compared with the true infection status obtained from post-mortem examination of the heart, pulmonary arteries, thoracic venae cavae and lungs. The prevalence of the infection by adult worms at necropsy was 63%. The sensitivity of the tests ranged from 60% (capillary tube) to 81% (Diasystems) and the specificity from 88% (filtration) to 98% (PetChek). The results of all the tests differed significantly (p<0.01) from those obtained at necropsy. The sensitivity of the tests was also assessed with respect to the differing numbers of worms in the hosts. A positive correlation between the worm burden and the sensitivity was observed in all the tests. It is apparent that the ELISA methods were better able to detect cases with a low number of worms than the haematological tests.Abbreviations AC accuracy - CB clotted blood - CT capillary tube - DI Diasystems - DS direct smear - ELISA enzyme-linked immunosorbent assay - FI filtration - MK modified Knott - NPV negative predictive value - PE PetChek - PPV positive predictive value - SE sensitivity - SP specificity - UN Uni-Tec     

The Early Effects of Clostridium perfringens Type D Epsilon Toxin in Ligated Intestinal Loops of Goats and Sheep

Clostridium perfringens type D produces enterotoxaemia in goats, sheep and other animals. The disease is caused by C. perfringens epsilon toxin and, while enterotoxaemia in goats is usually characterized by enterocolitis, the disease in sheep is characterized by systemic lesions (such as lung and brain oedema) with minor and inconsistent changes observed in the intestine. A possible explanation for these differences is that epsilon toxin is more promptly absorbed by the ovine than by the caprine intestine. In an attempt to clarify this, we examined the early effects of epsilon toxin on caprine and ovine intestine. Intestinal loop assays were performed to analyse the physiological and morphological changes induced by epsilon toxin in the intestine of these species. Fluid accumulation was observed in caprine and ovine ileum and colon treated with epsilon toxin. Ileal loops from goats treated with epsilon toxin retained sodium and water earlier than ovine ileal loops treated with the same toxin. Histological analysis showed morphological alterations in the colon of both species as early as 2 h after the commencement of epsilon toxin treatment; these changes were more marked in goats than in sheep. No morphological changes were observed in the ileum of either species after 4 h incubation with epsilon toxin. These results suggest that epsilon toxin modifies ion and water transport in the small and the large intestine of goats and sheep through different mechanisms.     

Protection against Brucellosis in Goats,Five Years after Vaccination with Reduced-Dose Brucella melitensis Rev 1 Vaccine

The protection conferred by the reduced-dose Rev 1 Brucella melitensis vaccine in goats that had been immunized 5 years previously was evaluated. Sixteen goats vaccinated 5 years before with Rev 1 (1 x 10(5) cfu) and 5 non-vaccinated goats were challenged with B. melitensis 16M (4 x 10(5) cfu) using the conjunctival route. After giving birth or aborting, the goats were sacrificed and tissue samples were taken for bacteriological study. The challenge strain was recovered in 12%, of the animals from the vaccinated group, and in (80% of the control group. It is concluded, therefore that the use of reduced-dose Rev 1 protects goats vaccinated in endemic areas for at least 5 years after immunization.     

Serological Survey of Babesia bovis and Anaplasma marginale in cattle in Tete Province,Mozambique

A serological survey of bovine babesiosis and anaplasmosis in communal cattle was conducted in the northwestern province of Tete, Mozambique. Blood was collected from cattle ranging from 4 to 15 months old from randomly selected farms from six districts. Thirty-nine per cent of all 478 calves tested in Tete Province were seropositive to the ELISA for Babesia bovis antibodies and 63% of all calves were seropositive in the card agglutination test for Anaplasma marginale. Seroprevalence of B. bovis ranged from 22.8% in Tete City District to 48.1% in Angonia District. For A. marginale, it ranged from 34.4% in Angonia District to 87.3% in Moatize District. The dominant factor affecting seroprevalence for both haemoparasites was district and there was a trend for higher intensity of tick control to be associated with a higher seroprevalence of B. bovis and a lower seroprevalence of A. marginale. The obvious differences were the low prevalence of B. bovis in Tete City Council District and the low prevalence of A. marginale in Angonia District. The levels of exposure to B. bovis seen in our study are well below any that could be considered to be consistent with endemic stability, yet they are sufficiently high to ensure that clinical disease would be a risk. The seroprevalence of A. marginale, however, suggests that endemic stability with respect to this disease could exist in districts other than Angonia. There was no strong and consistent relationship between the intensity of control and the likelihood of seropositivity to either of the diseases.     

Comparative Pathogenesis of Experimental Infections with Salmonella gallinarum in Local and Commercial Chickens

The pathogenicity of a virulent strain of Salmonella gallinarum was studied in local chickens and commercial layers. Sixty 4-month-old chickens were used. Of these, 50 chickens were orally infected with S. gallinarum, comprising 25 commercial layers and 25 local chickens. Five chickens in each group were used as uninfected negative controls. The clinical signs and pathological features of acute, subacute and chronic fowl typhoid were observed in both groups. Chickens in both groups seroconverted, but the antibody titre was significantly higher (p<0.001) in the commercial layers. The antibody titre remained high to the end of the experiment in all the surviving chickens. Only one commercial layer chicken died during the course of the experiment. The PCV decreased significantly (p<0.001) in the infected chickens of both groups as compared to the controls. The viable cell count of S. gallinarum in the liver and spleen reached a maximum on day 9 after infection in both groups. However, there was a significantly higher cell count (p<0.05) in the commercial layers. The severity of the disease appeared to be slightly greater in the commercial layers, although the susceptibility was similar in both groups. It was concluded that, under experimental conditions, local chickens are just as susceptible to S. gallinarum infection as are commercial layers.     

Efficacy of Albendazole and Levamisole against Gastrointestinal Nematodes of Sheep and Goats in Morogoro,Tanzania

A study was conducted to determine the efficacy of albendazole after it had been withdrawn from use due to the development of resistant strains of nematodes about ten years ago. The study also aimed to determine the present efficacy of levamisole, which had been recommended to replace albendazole. On one farm, the sheep and goats were divided into two groups, one group of each serving as the untreated control, while the other was treated with levamisole. The sheep on the other farm were divided into three groups, one serving as the untreated control group, the second being treated with levamisole and the third being treated with albendazole. Faecal samples were collected one day before treatment, and again 10 days after treatment. Anthelmintic efficacy was determined by the faecal egg count reduction test. Ten days after treatment, the sheep treated with levamisole on the first farm had a 98% reduction in faecal egg count, with a 95% confidence limit of 76%. The goats on the same farm had a 97% reduction in faecal egg count, with a 95% lower confidence limit of 81%. At the second farm, 10 days after treatment, sheep treated with levamisole had a 99.4% reduction in faecal egg count, with a 95% lower confidence limit of 88.9%, whereas the sheep treated with albendazole only had a 59.4% reduction in faecal egg count, with a 95% lower confidence limit of –19.6%. The study indicated that the gastrointestinal nematodes of sheep at the Department of Animal Science and Production farm were still resistant to albendazole about ten years after this anthelmintic had been withdrawn from use. A reduced efficacy of levamisole was suspected.     

贵州某野生动物园长臂猿流感病毒、支原体及巴氏杆菌混合感染的诊治

为弄清贵州某野生动物园长臂猿死亡的原因,本试验采用流行病学调查、临床症状观察、病理剖检诊断和RT-PCR检测确诊等方法,对该野生动物园发病长臂猿进行了诊断。试验结果显示,流行病学调查、剖检病理初步诊断该野生动物园长臂猿疑似流感病毒、支原体和细菌混合感染,RT-PCR/PCR检测确诊发病长臂猿为流感病毒、支原体混合感染,细菌分离培养、生化特性鉴定和动物致病性试验确诊为多杀性巴氏杆菌感染。结果表明造成该野生动物园长臂猿发病死亡的原因为流感病毒、支原体和多杀性巴氏杆菌混合感染。根据诊断及药敏试验结果,制定出了免疫预防及治疗措施。     

Listeric Infections in Humans and Animals in the Indian Subcontinent: A Review

Listeriosis is an important bacterial zoonosis caused by the intracellular pathogen Listeria monocytogenes. The disease has been reported in animals from the Indian subcontinent, usually in the form of sporadic cases but occasionally as outbreaks. Cases of listeriosis arise mainly from the ingestion of contaminated food. Listeriosis has been reported to cause encephalitis, abortion, mastitis, repeat breeding and endometriosis in animals. Listeric infections occur in children and women with a poor obstetric history. The epidemiological aspects and pathogenesis of listeriosis in animals and humans are not yet fully understood. This review offers comprehensive information on experimental studies and field cases in animals and on cases of human listeriosis. There are also sections on isolation from foods, diagnosis and treatment in humans and animals.