No indication of Coxiella burnetii infection in Norwegian farmed ruminants.

BACKGROUND: Infection with Coxiella burnetii, the cause of Q-fever, has never been detected in Norwegian animals. Recognising the increasing prevalence of the infection in neighbouring countries, the aim of the study was to perform a survey of Norwegian farmed ruminants for the prevalence of C. burnetii infection. RESULTS: Milk and blood samples from more than 3450 Norwegian dairy cattle herds, 55 beef cattle herds, 348 dairy goat herds and 118 sheep flocks were serologically examined for antibodies against C. burnetii. All samples were negative for antibodies against C. burnetii. The estimated prevalences of infected herds were 0 (95% confidence interval: 0% - 0.12%), 0 (0% - 12%), 0 (0% - 1.2%) and 0 (0% - 10%) for dairy cattle herds, beef cattle herds, goat herds and sheep flocks, respectively. CONCLUSIONS: The study indicates that the prevalence of C. burnetii infection in farmed Norwegian ruminants is low, and it cannot be excluded that Norway is free of the infection. It would be beneficial if Norway was able to maintain the current situation. Therefore, preventive measures should be continued.

Evaluation of three serological tests for diagnosis of Maedi-Visna virus infection using latent class analysis.

Maedi-Visna virus (MVV) infection in sheep is present in several European countries, including Norway. The current Norwegian surveillance and control programme for MVV infection uses three serological tests: an agar gel immunodiffusion test (AGID) and two commercially available indirect ELISAs (Institut Pourquier, P-ELISA and HYPHEN BioMed, H-ELISA). From 18 flocks with suspected or confirmed MVV infection, sera from naturally infected sheep were obtained, and sensitivity (Se) and specificity (Sp) of the three tests were estimated in absence of a perfect reference test using latent class models in a Bayesian analysis. The AGID had higher Sp (95% posterior credibility interval (PCI) [98.4; 99.9]) than either ELISA (95% PCI: P-ELISA, [95.1; 99.0]; H-ELISA, [91.4; 96.6]), but much lower Se (95% PCI: AGID, [41.4; 59.8]; P-ELISA, [92.7; 100.0]; H-ELISA, [90.9; 99.4]). Currently the P-ELISA is used for screening and positive samples are subsequently confirmed by a setup using all three tests in a serial reading. The Se and Sp of the serial interpretations with and without the H-ELISA were estimated. The results suggested that the H-ELISA could be dropped as a confirmatory test as the Se of the three test serial reading was reduced significantly without adding a significant improvement of the Sp compared to the serial reading of the P-ELISA and AGID alone. However, the perceived cost of false positives versus false negatives will influence this decision. Estimates of the predictive values for the tests and combinations suggested that the P-ELISA is a good choice of screening, but confirmatory tests are needed to achieve acceptable levels of positive predictive values.

Prevalence of Toxoplasma gondii antibodies in wild red deer, roe deer, moose, and reindeer from Norway.

Serum samples from 4339 wild cervids collected in Norway were tested for antibodies against Toxoplasma gondii using the direct agglutination test. The association between seroprevalence and species, sex, age, and geographic region was investigated. Positive titers (> or =1:40) were found in 33.9% of 760 roe deer (Capreolus capreolus); 12.6% of 2142 moose (Alces alces); 7.7% of 571 red deer (Cervus elaphus); and 1.0% of 866 reindeer (Rangifer tarandus). The seroprevalences were significantly different between the species. There was a significant increase in prevalence with age in roe deer, moose, and red deer, except from yearling to adult in red deer. A significant age-sex interaction was found in moose, and the effect of age was most distinct for females. No association between seropositive animals and sex was found for roe deer and red deer. There were significant differences in prevalence between geographic regions in roe deer and male moose. A widespread exposure to T. gondii in Norwegian cervids is documented, and meat from Norwegian cervids, particularly roe deer, should be regarded a potential source of infection for humans.

Antibodies to ruminant alpha-herpesviruses and pestiviruses in Norwegian cervids.

A serologic survey revealed that Norwegian populations of free-ranging reindeer (Rangifer tarandus tarandus), roe deer (Capreolus capreolus), red deer (Cervus elaphus), and moose (Alces alces) have been exposed to alpha-herpesviruses and pestiviruses. A total of 3,796 serum samples collected during the period 1993-2000 were tested in a neutralization test for antibodies against bovine herpesvirus 1 (BHV-1) or cervid herpesvirus 2 (CerHV-2), and 3,897 samples were tested by a neutralization test and/or enzyme-linked immunosorbent assay for antibodies against bovine viral diarrhea virus (BVDV). Antibodies against alpha-herpesvirus were found in 28.5% of reindeer, 3.0% of roe deer, and 0.5% of red deer, while all moose samples were negative. In reindeer, the prevalence of seropositive animals increased with age and was higher in males than females. Antibodies against BVDV were detected in 12.3% of roe deer, 4.2% of reindeer, 2.0% of moose and 1.1% of red deer. The results indicate that both alpha-herpesvirus and pestivirus are endemic in reindeer and pestivirus is endemic in roe deer in Norway. The viruses may be specific cervid strains. Seropositive red deer and moose may have become exposed as a result of contact with other ruminant species.

Serologic survey for antibodies against Mycobacterium a vium subsp. paratuberculosis in free-ranging cervids from Norway.

Affinity between protein-G and immunoglobulins from red deer (Cervus elaphus), moose (Alces alces), roe deer (Capreolus capreolus), and reindeer (Rangifer tarandus tarandus) was tested in a competition binding assay. Sera from red deer, reindeer, and moose inhibited the assay less than sera from cattle (less affinity), whereas sera from roe deer showed a slightly higher affinity to protein-G than did sera from cattle. The conclusion was made that protein-G could be used instead of anti-species antibodies for these cervid species, where the aim of the screening was to look for exposure or lack of exposure to mycobacteria in the tested populations. Serologic screening of 1,373 free-ranging cervids for antibodies against Mycobacterium avium subsp. paratuberculosis was conducted. All sera were tested by a protein-G-based antigen-absorbed enzyme-linked immunosorbent assay (ELISA). Seropositive moose (10/537; 1.9%), red deer (14/371; 3.8%), roe deer (6/49; 12.2%), and semidomesticated reindeer (11/325; 3.4%) were found, whereas wild reindeer (n = 91) were seronegative. In addition, the red deer sera were tested with a commercial ELISA, by which two animals tested positive and nine were suspicious of having M. avium subsp. paratuberculosis antibodies. Tissue samples and feces from 10 moose originating from a population with a clustering of seropositive animals were investigated by histology and bacteriology with negative results. Paratuberculosis has never been diagnosed in free-ranging or farmed cervid species in Norway. Thus, further studies are indicated to prove that the present findings reflect an infection with M. avium subsp. paratuberculosis.

Seroprevalence of Toxoplasma gondii infection in Norwegian dairy goats.

BACKGROUND: Toxoplasma gondii is a major problem for the sheep industry as it may cause reproduction problems. The importance of T. gondii in Norwegian goat herds is uncertain, but outbreaks of toxoplasmosis in dairy goat farms have been recorded. The aim of this study was to describe the prevalence of T. gondii infection in Norwegian dairy goats by using serology. FINDINGS: Goat serum originally collected as part of two nationwide surveillance and control programmes between 2002 and 2008 were examined for T. gondii antibodies by using direct agglutination test. In total, 55 of 73 herds (75%) had one or more serologically positive animals, while 377 of 2188 (17%) of the individual samples tested positive for T. gondii antibodies. CONCLUSIONS: This is the first prevalence study of T. gondii infection in Norwegian goats. The results show that Norwegian goat herds are commonly exposed to T. gondii. Nevertheless, the majority of goat herds have a low prevalence of antibody positive animals, which make them vulnerable to infections with T. gondii during the gestation period.