Enzyme immunoassay for surveillance of Q fever

An enzyme-linked immunosorbent assay (ELISA) was developed to monitor antibodies against Coxiella burnetii among animal populations used in research and teaching facilities. Various antigenic components of C burnetii prepared from phase I and phase II whole cells and commercially available antigens were evaluated. A trichloroacetic acid extract was selected for routine use. There was a linear relationship between the transformed absorbance readings of the ELISA results and microagglutination (MA) titers. Comparison between positive or negative results of the MA test and ELISA gave 98.6% concordance. Using the MA test as the standard, ELISA results were 97.8% sensitive and 100% specific. The efficacy of ELISA was evaluated by testing ruminants with known histories of C burnetii infection. Antibody prevalence was 0 in 117 sheep with no history of C burnetii infection, 22% in 145 naturally infected sheep used for research, and 53% in 115 sheep used for vaccine field trials. Forty-eight percent of 120 dairy cows and 52% of 79 goats from endemically infected herds were seropositive. These results indicate that ELISA should be the test of choice for mass screening and surveillance of animals when Q fever is a suspected biohazard.     

Coxiella burnetii in bulk tank milk samples from dairy goat and dairy sheep farms in The Netherlands in 2008

In 2007, a human Q fever epidemic started, mainly in the south eastern part of The Netherlands with a suspected indirect relation to dairy goats, and, to a lesser degree, to dairy sheep. This article describes the Q fever prevalences in Dutch dairy goat and dairy sheep bulk tank milk (BTM) samples, using a real-time (RT) PCR and ELISA. Results of BTM PCR and ELISA were compared with the serological status of individual animals, and correlations with a history of Q fever abortion were determined. When compared with ELISA results, the optimal cut-off value for the RT-PCR was 100 bacteria/ml. In 2008, there were 392 farms with more than 200 dairy goats, of which 292 submitted a BTM sample. Of these samples, 96 (32.9 per cent) were PCR positive and 87 (29.8 per cent) were ELISA positive. All farms with a history of Q fever abortion (n=17) were ELISA positive, 16 out of 17 were also PCR positive. BTM PCR or ELISA positive farms had significantly higher within-herd seroprevalences than BTM negative farms. In the south eastern provinces, the area where the human Q fever outbreak started in 2007, a significantly larger proportion of the BTM samples was PCR and ELISA positive compared to the rest of The Netherlands. None of the BTM samples from dairy sheep farms (n=16) were PCR positive but three of these farms were ELISA positive. The higher percentage of BTM positive farms in the area where the human Q fever outbreak started, supports the suspected relation between human cases and infected dairy goat farms.     

Ehrlichia ruminantium seroprevalence in domestic ruminants in Ghana; I. Longitudinal survey in the Greater Accra Region

Serum samples collected monthly over a 34-month period from cattle, sheep and goats in the Greater Accra Region of Ghana were tested for antibodies to Ehrlichia (previously Cowdria) ruminantium, the causative agent of heartwater, by polyclonal competitive ELISA (PC-ELISA). Maternal antibodies, detected in about half of animals followed from under 1 month old, declined to negative levels within 2–4 months. Amblyomma variegatum tick vectors were present on livestock in rural areas throughout the year, and first seroconversion occurred at any age, although the majority of calves seroconverted between 1 and 10 months old, sheep by 11 months, and goats by 7 months. All the cattle in the study became seropositive by 20 months of age, except one animal which subsequently died of heartwater. Following seroconversion, 25% of bovine sera tested negative in the PC-ELISA. Just over half the sheep in the survey seroconverted before or during the study period; following seroconversion, less than 3% of ovine sera became PC-ELISA negative. About a quarter of the goats seroconverted, and 34% of their post-seroconversion sera tested negative in the PC-ELISA. Overall, the serology indicated that virtually all cattle on the survey farms were exposed to E. ruminantium without suffering disease, but that a substantial proportion of sheep and goats escaped exposure and thus formed a susceptible population. E. ruminantium was detected in brains of 14, 36 and 4% of cattle, sheep and goats submitted for post mortem at the Accra Veterinary Laboratory, indicating that sheep were most at risk from heartwater disease.     

Evaluation of four serological tests for the diagnosis of caprine melioidosis

A complement fixation (CF) test, 2 indirect haemagglutination (IHA-A; IHA-L) tests which differed in antigen preparation and technique, and a microtitre agglutination (MA) test were compared in the serodiagnosis of melioidosis in goats. One hundred and eighteen experimental serums and 3143 field serums from goats in endemic and non-endemic areas of north Queensland were used in the evaluation. Culture of samples for Pseudomonas pseudomallei from 112 goats provided substantiating evidence of infection. The IHA-A test was the most sensitive, and the CF test the most specific. We advocate the use of the IHA-A as a screening test followed by the CF test for confirmation of active melioidosis. The IHA-A test is the better indicator of past infection.     

Cohort study of natural transmission and two methods for control of caprine arthritis-encephalitis virus infection in goats on a California dairy.

A prospective observational cohort study of 361 dairy goat kids was conducted to compare 2 methods of controlling caprine arthritis-encephalitis virus infection under commercial dairy conditions. To compare effectiveness of feeding kids pasteurized milk vs serologic testing and segregation in addition to pasteurized milk feeding, goats were monitored up to the age of 30 months by use of monthly agar gel immunodiffusion testing. Survival analysis methods were used to determine whether age at seroconversion differed between the 2 groups. Significantly lower rates of seroconversion were observed in the segregated group (P < 0.001), compared with the nonsegregated group. Of 193 goats in the pasteurized milk-only group, 146 (75.6%) seroconverted within the 30-month study period, whereas infection was detected in 39 (23.2%) of 168 goats in the test/segregated group. Nonsegregated goats were 3.37 times more likely to seroconvert by 24 months of age, and 70.3% of seroconversions by 24 months of age could be attributed to nonsegregation. For age-specific intervals beyond 180 days of age, 70 to 100% of seroconversions could be attributed to lack of segregation. Cohort life tables for age at seroconversion were reported for each group. Type of colostrum fed, sex, and weaning group (season) were not significantly associated with age at seroconversion. Saanen goats had lower age-specific risk of seroconversion in the nonsegregated group alone and overall. Non-Saanen goats wee 1.5 times more likely to seroconvert than were Saanen goats, when adjusted for a possible confounding effect of weaning group. Results indicate that pasteurized milk feeding and routine test and segregation would be a substantially more effective means of control of the disease in dairy goat herds than would pasteurized milk feeding alone.     

Molecular investigation,isolation and phylogenetic analsysis of Coxiella burnetii from aborted fetus and ticks

Q fever is a zoonotic infection threatening human health, causing abortions in cattle, sheep and goats. Coxiella burnetii (C. burnetii) also causes serious problems such as low birth weight, infertility. This study is the first exemplary for analysis of Q fever around Black Sea region in Turkey. In the study, a total of 270 aborted fetuses (171 cattle, 79 sheep, 20 goats) and 1069 tick samples were aimed to be searched by PCR method. C. burnetii DNA was detected in 8 (2.96 %) of 270 sheep specimens while it could not be found in cattle and goat specimens. 406 sample pools were created from 1069 tick samples (490 male, 579 female) collected from 254 farm animals (187 cattle, 54 sheep, 13 goats) and 11 of these were stated positive. Tick species determined as C. burnetii positive were Hyalomma marginatum, Hyalomma anoliticum excavatum, Hyalomma detritum and Boophilus annulatus. Agent isolation was carried out within embryonated eggs. Agents were stained with Giemsa and was showed. Sequence analysis was performed for TUR/SAM/coxiella_1 (MN917207) isolate and phylogenetic tree was created. This tree, created in compliance with IS1111 transposon gene, did not form different branches in regard to host affiliation (goat, sheep, tick, human) and geographical distribution. As a result, an important zoonotic agent, C. burnetii was diagnosed in sheep aborted fetuses and the infection was proved to have spread among sheep herds in Black Sea region. Besides, 4 separate tick species found in our region hosted the agent and were found important for infection.     

Risk factors associated with the incidence of seroconversion to caprine arthritis-encephalitis virus in goats on California dairies.

Incidence of seroconversion to caprine arthritis-encephalitis virus (CAEV) was determined for 1,194 goats on 11 dairies, using 2 repeated annual herd tests for CAEV. Current life table methods were used to compare age-specific incidence of seroconversion for pasteurized milk-raised and unpasteurized milk-raised goats. Logistic regression models were used to determine the risk factors associated with CAEV seroconversion, and to estimate odds ratios for seroconversion for various factor levels. Goats raised by unpasteurized milk-feeding methods were 2.5 to 6.7 times more likely to seroconvert than were goats raised by pasteurized milk-feeding methods, depending on the method of comparison. Similarly, 61.6 to 85.0% of seroconversions in yearling goats possibly were attributable to unpasteurized milk feeding. Among yearling goats, CAEV seroconversion was associated with feeding method, breed, and source of goat (herd of origin) when the effect of dairy was considered. In addition to the 6.7 times greater risk of seroconversion for unpasteurized milk-raised goats, yearling goats of the Saanen and Toggenburg breeds were 2.2 and 3.3 times, respectively, more likely to seroconvert than were Alpine yearling goats. Yearling goats purchased from another source were less likely to seroconvert than were yearlings raised on the dairy where they were studied. Among goats > 1 year old, age was associated with risk of seroconversion. Goats that were 3 years old or were > or = 4 years old were 1.7 and 3.2 times, respectively, more likely to seroconvert than were 2-year-old goats, when adjusted for effect of dairy. The effects of dairy were significant (P < or = 0.001) in yearling and older goats.     

Q Fever in Alberta,Canada: 1998–2011

Establishing the diagnosis of Q fever (Coxiella burnetii) is important in directing the application of therapy to prevent severe manifestations of the infection. In Alberta, Canada, the presence of high livestock density creates a significant risk of infection, but to date, there has been no comprehensive analysis of local Q fever epidemiological trends and exposure patterns. Between 1998 and 2011, there were 39 cases and an overall adjusted case rate of 0.087 per 100 000 person‐years. Cases were identified most commonly during the May–June season (Figure 2). The median age at date of diagnosis was 49.0 (range: 8.7–71.5) with slightly higher percentage of cases in men (56.4%) than in women (43.6%). There was an apparent geographical clustering of cases. The majority of these cases, with exposure data (n = 31), reported contact with farms and/or livestock, predominantly cattle (6), sheep (5) and goats (5). Cases tended to occur in census divisions with higher density of sheep, goats and cattle. Our findings suggest the need for an increase in targeted messages about Q fever to those in the livestock industry, as more targeted case finding among patients with a high index of suspicion for Q fever. In addition, widespread implementation of a standard questionnaire for cases would enhance surveillance of Q fever in Alberta.     

A long-term study in Angora goats experimentally infected with Mycobacterium avium subsp. paratuberculosis: clinical disease, faecal culture and immunological studies

Two longitudinal experiments involving Angora goats challenged with either bovine or ovine strains of Mycobacterium avium subspecies paratuberculosis (Map) have been conducted over a period of 54 and 35 months, respectively. Blood samples for the interferon-gamma (IFN-gamma) test and the absorbed ELISA and faecal samples for bacteriological culture were taken pre-challenge and monthly post-challenge. Persistent shedding, IFN-gamma production, seroconversion and clinical disease occurred earlier with the bovine Map gut mucosal tissue challenge inoculum than with cultured bacteria. The IFN-gamma responses of the gut mucosal tissue and bacterial challenge groups were substantially and consistently higher than those of the control group. The in vivo and cultured cattle strains were much more pathogenic for goats than the sheep strains with persistent faecal shedding, seroconversion and clinical disease occurring in the majority of bovine Map challenged goats. With the ovine Map, 3 goats developed persistent antibody responses but only one of these goats developed persistent faecal shedding and clinical disease. However, there was no significant difference between the IFN-gamma responses of the tissue challenged, bacterial challenged and control groups. Compared with sheep, the ELISA appeared to have higher sensitivity and the IFN-gamma test lower specificity.     

绵羊肺炎霉形体的血清学调查

本试验旨在了解绵羊肺炎霉形体在山西省雁北地区的流行状况,为该病的预防和控制提供科学依据,对雁北地区的大同市、朔州市和忻州市的12个县,随机抽取96份血清样本,用间接血凝试验进行血清学检测。共检出37份阳性血清,绵羊肺炎霉形体的总体平均阳性为38.54%,其中忻州市阳性率最高,为44%,朔州市最低,为25%;县(区)阳性率以大同市浑源县最高,达66.7%;饲养方式、环境卫生、动物年龄等对本病的感染均有影响,其中舍饲羊阳性率达50%,高于总体平均阳性率和半舍饲阳性率。结果提示,山西省雁北地区绵羊肺炎霉形体阳性率较高,通风不良和环境卫生较差为主要诱发因素。     

Differential haematological effects of tick-borne fever in sheep and goats

Tick-borne fever (TBF) is a rickettsial disease of domestic and wild ruminants in temperate climates. It is characterized by high fever and severe leukopenia. In the present study, the possible difference in the severity of disease in sheep and goats was investigated by inoculating one group of eight goats and one group of eight sheep with the Old Sourhope (OS) strain of Ehrlichia (Cytoecetes) phagocytophila. All sheep and goats experimentally infected with E. phagocytophila reacted with fever and rickettsiaemia, but there were significant differences between goats and sheep in the severity of clinical disease, the duration and magnitude of fever, the magnitude of rickettsiaemia and the patterns of reduction in the number of total leucocytes. Sheep reacted with fever significantly earlier than goats and the febrile period lasted for a significantly longer period. In contrast, the magnitude of rickettsiaemia was significantly higher in goats than in sheep. Infection with TBF was characterized by a transient increase in the number of neutrophils, which was quickly followed by an acute reduction in the number of lymphocytes and a prolonged reduction in the number of neutrophils in both sheep and goats. In both groups of animals, infection with TBF was also characterized by significant reductions in the total number of red blood cells (RBCs), thrombocytes and packed cell volume (PCV) and the concentration of haemoglobin (Hb). However, the mean corpuscular volume (MCV) and mean corpuscular Hb (MCH) were significantly increased in sheep only.     

Resistance to classical scrapie in experimentally challenged goats carrying mutation K222 of the prion protein gene

ABSTRACT: Susceptibility of sheep to scrapie, a transmissible spongiform encephalopathy of small ruminants, is strongly influenced by polymorphisms of the prion protein gene (PRNP). Breeding programs have been implemented to increase scrapie resistance in sheep populations; though desirable, a similar approach has not yet been applied in goats. European studies have now suggested that several polymorphisms can modulate scrapie susceptibility in goats: in particular, PRNP variant K222 has been associated with resistance in case-control studies in Italy, France and Greece. In this study we investigated the resistance conferred by this variant using a natural Italian goat scrapie isolate to intracerebrally challenge five goats carrying genotype Q/Q 222 (wild type) and five goats carrying genotype Q/K 222. By the end of the study, all five Q/Q 222 goats had died of scrapie after a mean incubation period of 19 months; one of the five Q/K 222 goats died after 24 months, while the other four were alive and apparently healthy up to the end of the study at 4.5 years post-challenge. All five of these animals were found to be scrapie negative. Statistical analysis showed that the probability of survival of the Q/K 222 goats versus the Q/Q 222 goats was significantly higher (p = 0.002). Our study shows that PRNP gene mutation K222 is strongly associated with resistance to classical scrapie also in experimental conditions, making it a potentially positive target for selection in the frame of breeding programs for resistance to classical scrapie in goats.     

An ELISA with Brucella lipopolysaccharide antigen for the diagnosis of B. melitensis infection in sheep and for the evaluation of serological responses following subcutaneous or conjunctival B. melitensis strain Rev 1 vaccination.

An indirect enzyme-linked immunosorbent assay (ELISA) with unpurified Brucella melitensis smooth lipopolysaccharide (S-LPS) as antigen was evaluated for the serological diagnosis of B. melitensis infection in sheep in comparison with the Rose Bengal (RB), complement fixation (CF), radial immunodiffusion (RID), microplate agglutination (MA) and rivanol agglutination (RIV) tests. Tests RB and CF detected as positive each of the 77 sera from B. melitensis-infected animals tested, the RID (74), MA (76) and the RIV (72) were less sensitive. However, all tests compared were negative when 77 sera from Brucella-free rams were tested. While subcutaneous Rev 1 vaccination induced high response levels in any of the tests, low level responses were obtained upon conjunctival vaccination, particularly in ELISA and RID tests.     

Occurrence and risk factors of Coxiella burnetii in domestic ruminants in Lebanon

Coxiella burnetii causes diseases in humans (Q fever) and animals, domestic ruminants playing a major role in the epidemiology of the infection. Information on C. burnetii infection in Lebanon is scanty. In order to assess the prevalence of C. burnetii infection in ruminants, a cross-sectional study was undertaken in 2014. A total of 1633 sera from ruminants (865 cattle, 384 sheep and 384 goats) from 429 farms (173 cattle, 128 sheep and 128 goats), in seven provinces of Lebanon were randomly selected and assayed for the presence of antibodies.39.86% of farms (95% CI: 35.23–44.56) resulted positive. The seroprevalence was 30.63% in Cattle-farms, 46.88% in sheep-farms and 45.31% in goat-farms.Milk samples collected from 282 seropositive animals (86 cows, 93 sheep and 103 goats) from 171 positive farms were tested by a high sensitive Real-Time PCR targeted to the IS1111 transposon of C. burnetii. The overall prevalence in farms was estimated to be 14.04%. Cattle-, sheep- and goat farm prevalence rates were 15.09%, 10% and 17.24%, respectively.The findings of the study show that C. burnetii prevalence in Lebanese domestic ruminants is related to animal species and farming practices. Indeed, the mixed herds with sheep (p < 0.01), the presence of common lambing/kidding areas (p < 0.001) in farms where the use of disinfectants was not a routine practice (p < 0.05) were identified as important risk factors.The results of the study provide baseline information for setting up herd management and public health measures for the prevention and control of Q fever in Lebanon.     

Comparison of infection rates of Oestrus ovis between sheep and goats kept in mixed flocks

Oestrosis is a nasal myiasis of sheep and goats caused by larvae of the fly Oestrus ovis and can lead to severe clinical signs, which together with the disturbance caused by the adult fly may result into serious economic losses. Infection rates and larval burdens are always higher in sheep than in goats after either natural or artificial infestation. The aim of this study was to compare the host preference of the adult fly O. ovis between sheep and goats in mixed flocks, where they are kept together under the same husbandry conditions and hence, are very similarly exposed to the fly preference. Blood sera samples were collected from a total of 397 sheep and 335 goats, from 43 mixed flocks located at different regions of Greece. Antibodies specific to O. ovis IgG were measured by ELISA. A flock was considered positive when at least one individual was positive, i.e. showed a seropositivity of >or=20% in relation to positive control sera. A total of 193 (48.6%) sheep and 58 (17.9%) goats were found to be seropositive against O. ovis. Thirty-eight (88.4%) out of 43 flocks had at least one seropositive animal. The mean seroconversion against O. ovis in animals from the different flocks was 38.6% and 13.6% for sheep and goats, respectively, whereas the variance of infection within each flock was 0-100%. The mean seropositivity between sheep that were found to be positive or negative was 60.6% and 5.4%, respectively, whereas the corresponding values between goats were 35.2% and 5.2%, respectively. No significant difference in the seroconversion values was noted between flocks from the different areas (P=0.817), whereas a very significant difference was observed between animal species (P=0.001). However, there was no significant difference when seroconversion comparisons were made within samples of the same animals species, sheep or goats from different flocks of all the regions included in the study (P=0.695). The results of this study clearly demonstrate that O. ovis has a widespread distribution in Greece, and the seroprevalence is significantly higher in sheep than goats (P=0.001).     

Risk factors for Brucella seropositivity in goat herds in eastern and western Uganda.

Cross-sectional prevalences and risk factors for Brucella seropositivity in goats in eastern and western Uganda were investigated. Serum was collected from 1518 goats randomly selected from 145 herds which had been identified using multistage sampling. The brucellosis card test (CT) and the Brucella melitensis tube-agglutination test (TAT) were used in parallel to detect antibodies against B. abortus and B. melitensis, respectively. Interviewer-administered questionnaires were used to collect information on goat health and management. This information was used in multivariable logistic-regression models to determine the risk factors for Brucella seropositivity in goat herds. For each analysis, a herd was considered positive if at least one goat in the herd tested positive for antibodies against Brucella and negative if none was positive.Four percent (55/1480) of the goats screened with the CT had antibodies against Brucella. The reactors were distributed in 13% (19/145) of the herds. The most-important herd-level risk factors identified were use of a hired caretaker as the primary manager of the operation compared to owner/family members (adjusted odds ratio (OR)=8.1; 95% CI 1.6, 39.7), keeping sheep in addition to goats (OR=6.0; CI 1.5, 23.7) compared to having no sheep, and free browsing (OR=4.7; 95% CI 1.0, 20.7) when compared to tethering or zero-grazing.Using the TAT, 10% (141/1446) of the goats tested positive. The positives were distributed in 43% (63/145) of the herds. Free browsing (OR=6.7; 95% CI 2.7, 16.9) when compared to tethering or zero-grazing and lack of veterinary care (OR=2.9; CI 1.3, 6.7) were the most-important factors identified in the multivariable model for B. melitensis herd seropositivity.To explore/reduce the risk of misclassification in a secondary analysis, herds were reclassified as positive if at least one goat tested positive on both tests and negative if none of the goats was positive on any of the two tests. Using this classification, 2% (30/1320; 95% CI 2, 3%) of the goats tested positive resulting in 13% (12/93) of the herds being positive. The distribution of the above risk factors by brucellosis herd-status (as defined by the second criterion) is also presented.     

Detection of contagious ovine ecthyma (orf) and risk factors for infection in small ruminants in Iran

The primary cause of contagious ecthyma is the orf virus, the parapoxvirus prototype. It is a viral problem observed in goat and sheep flocks in Iran, causing economic loss. Orf is a zoonosis with little epidemiological investigation present in Iran. The current research aims at determining the status of this virus, and a PCR was used as a confirmatory instrument. We sampled 668 goats and sheep and various breeding systems. Besides, the orf prevalence was studied, and vaccination efficacy was determined. Moreover, the potential risk factors surveyed for infection with ecthyma were identified. Samples were taken from goat and sheep flocks in the present cross-sectional research, and PCR was used for testing orf DNA. A checklist including animals’ general information was completed. Data were analyzed using univariate tests (chi-square and t-tests) and multivariable binary logistic regression analysis. Three hundred one (45%) goats and sheep detected orf DNA. The age of 70% of positive cases was below one month. Ecthyma infection was significantly higher in imported breeds (87.3%) than indigenous (39.3%). Ninety-six percent of infected goats and sheep in the present work were not vaccinated against ecthyma. The high prevalence of the orf virus was confirmed among goat and sheep flocks in Iran. It is necessary to train ranchers regarding sanitary actions, quarantine, and application of orf vaccination plans.     

Serologic and virologic investigations into pestivirus infection in wild and domestic ruminants in the Pyrenees (NE Spain)

An outbreak of disease associated to a border disease virus was described in the Southern chamois (Rupicapra pyrenaica) in Spain in 2002. Sera and/or spleen samples from 57 mouflon, 15 red deer, 21 roe deer, 3 fallow deer, 55 sheep, 32 cattle, and 68 goats sharing the chamois habitat were studied. An antibody ELISA test yielded an inconclusive result in 2 mouflon and positive results in 5 goat sera. Comparative virus neutralization tests were performed on the 2 inconclusive mouflons, 3 of the 5 seropositive goats, 55 sheep and 32 cattle, using 6 pestivirus strains. Positive results were obtained in 1 mouflon, 2 goats, 69% of sheep and 78% of cattle. Virological investigations performed with an antigen ELISA test yielded negative results in 21 goats and 39 mouflons, the result in 1 mouflon being inconclusive. PCR performed on 12 goats and the inconclusive mouflon gave negative results. These results suggested that it is unlikely that chamois BDV is infecting wild and domestic ruminants.     

A serologic survey of viral infections in captive ungulates in Turkish zoos

Zoos and zoologic gardens make optimal environments for interspecies transmission of viral infections. There are seven zoos and several small zoologic collections in Turkey. This study aimed to determine the current status of viral infections in captive ungulates living in these environments. Blood samples were taken from 163 captive animals from two zoos. There were 39 Cameroon sheep (Ovis ammon f aries), 11 Barbary sheep (Ammotragus lervia), 57 pygmy goats (Capra hircus), 9 Angora goats (Capra hircus), 21 mountain goats (Capra aegagrus-aegagrus), 7 llamas (Lama glama), 8 Persian goitred gazelle (Gazella subgutturosa subgutturosa), 7 Caspian red deer (Cervus elaphus maral), 2 fallow deer (Dama dama), and 2 camels (Camelus dromedarius). Antibodies against bovine viral diarrhea virus (BVDV), bovine herpesvirus-1 (BHV-1), bovine adenoviruses (BAV-1 and -3), parainfluenzavirus 3 (PI-3), and bluetongue viruses (BTV-4 and -9) were investigated using the virus neutralization test, and malignant catarrhal fever (MCF) antibodies were screened by ELISA. All animals were negative for BVDV and BHV-1 antibodies. Seroprevalence of BAV-1, BAV-3, PI-3, BRSV, BT-4, BT-9, and MCF were detected as follows: 46.6%, 60.1%, 0.6%, 7.3%, 1.8%, 1.2%, and 51.6%, respectively. Seroprevalence of BAVs and MCF were more common than all other viruses (P < 0.0001). Ten sheep (37.0%), 48 goats (84.2), and 1 Ilama (14.2%) were the only species positive for MCF antibodies. Prevalence of BRSV and MCF antibodies were found to be significantly higher in goats than in sheep. BTV antibodies were detected both in Cameroon sheep and mountain goats and suggest that zoo animals are at risk for BTV in endemic regions.     

Comparative diagnostic potential of three serological tests for abortive Q fever in goat herds

Performances of an ELISA, an immunofluorescence assay (IFA) and a complement fixation test (CFT) were assessed for detecting antibodies against Coxiella burnetii after Q fever abortions in naturally infected goats. The goal of the study was to provide information useful for veterinary serodiagnosis in regard to categories of goats either experiencing Q fever abortion or not, blood sampling times and recommended cut-offs. The study was conducted on eight goat herds with evidence of C. burnetii abortions. In each herd, at least 5 goats that had aborted and 10 goats prior to parturition or at term were monitored 15, 30 and 60 days (D15, D30, D60) after the onset of Q fever abortion. The overall CFT results distribution did not differ between the two groups of goats and showed poor agreement with the ELISA results. In contrast, the ELISA and IFA results revealed comparable significant differences, but overall the ELISA test was slightly more sensitive than the IFA test. Seroprevalence, according to ELISA and IFA respectively, was higher in the aborting (88% and 82%) than in the non-aborting group (60% and 50%). High levels of serum antibodies were detected in goats post-abortion with an average of 114 %OD using ELISA and a log10(titer) of 2.4 using IFA. Strongly positive ELISA (%OD>80) and positive IFA results (log10(titers)>1.9) were significantly associated with abortion. Sampling on D15 gave the best association with ORs of 10 for ELISA and 6 for IFA. The practical interest of these results is discussed.