Persistent infections after natural transmission of bovine viral diarrhoea virus from cattle to goats and among goats

Bovine viral diarrhoea virus (BVDV) is an economically important pathogen of cattle worldwide. Infection of a pregnant animal may lead to persistent infection of the foetus and birth of a persistently infected (PI) calf that sheds the virus throughout its life. However, BVD viruses are not strictly species specific. BVDV has been isolated from many domesticated and wild ruminants. This is of practical importance as virus reservoirs in non-bovine hosts may hamper BVDV control in cattle. A goat given as a social companion to a BVDV PI calf gave birth to a PI goat kid. In order to test if goat to goat infections were possible, seronegative pregnant goats were exposed to the PI goat. In parallel, seronegative pregnant goats were kept together with the PI calf. Only the goat to goat transmission resulted in the birth of a next generation of BVDV PI kids whereas all goats kept together with the PI calf aborted. To our knowledge, this is the first report which shows that a PI goat cannot only transmit BVD virus to other goats but that such transmission may indeed lead to the birth of a second generation of PI goats. Genetic analyses indicated that establishment in the new host species may be associated with step-wise adaptations in the viral genome. Thus, goats have the potential to be a reservoir for BVDV. However, the PI goats showed growth retardation and anaemia and their survival under natural conditions remains questionable.

Ecosystem impacts of feral rabbits on World Heritage sub-Antarctic Macquarie Island: A palaeoecological perspective

The introduction and establishment of non-indigenous species through human activities often poses a major threat to natural biodiversity. In many parts of the world management efforts are therefore focused on their eradication. The environment of World Heritage sub-Antarctic Macquarie Island has been severely damaged by non-indigenous species including rabbits, rats and mice, introduced from the late AD 1800s. An extensive eradication programme is now underway which aims to remove all rabbits and rodents. To provide a long-term context for assessing the Island's pre-invasion state, invasion impacts, and to provide a baseline for monitoring its recovery, we undertook a palaeoecological study using proxies in a lake sediment core. Sedimentological and diatom analyses revealed an unproductive catchment and lake environment persisted for ca. 7100 years prior to the introduction of the invasive species. After ca. AD 1898, unprecedented and statistically significant environmental changes occurred. Lake sediment accumulation rates increased >100 times due to enhanced catchment inputs and within-lake production. Total carbon and total nitrogen contents of the sediments increased by a factor of four. The diatom flora became dominated by two previously rare species. The results strongly suggest a causal link between the anthropogenic introduction of rabbits and the changes identified in the lake sediments. This study provides an example of how palaeoecology may be used to determine baseline conditions prior to the introduction of non-indigenous species, quantify the timing and extent of changes, and help monitor the recovery of the ecosystem and natural biodiversity following successful non-indigenous species eradication programmes.

The brown coat colour of Coppernecked goats is associated with a non-synonymous variant at the TYRP1 locus on chromosome 8

The recent development of a goat SNP genotyping microarray enables genome-wide association studies in this important livestock species. We investigated the genetic basis of the black and brown coat colour in Valais Blacknecked and Coppernecked goats. A genome-wide association analysis using goat SNP50 BeadChip genotypes of 22 cases and 23 controls allowed us to map the locus for the brown coat colour to goat chromosome 8. The TYRP1 gene is located within the associated chromosomal region, and TYRP1 variants cause similar coat colour phenotypes in different species. We thus considered TYRP1 as a strong positional and functional candidate. We resequenced the caprine TYRP1 gene by Sanger and Illumina sequencing and identified two non-synonymous variants, p.Ile478Thr and p.Gly496Asp, that might have a functional impact on the TYRP1 protein. However, based on the obtained pedigree and genotype data, the brown coat colour in these goats is not due to a single recessive loss-of-function allele. Surprisingly, the genotype distribution and the pedigree data suggest that the (496) Asp allele might possibly act in a dominant manner. The (496) Asp allele was present in 77 of 81 investigated Coppernecked goats and did not occur in black goats. This strongly suggests heterogeneity underlying the brown coat colour in Coppernecked goats. Functional experiments or targeted matings will be required to verify the unexpected preliminary findings.

Characterization of small ruminant lentivirus A4 subtype isolates and assessment of their pathogenic potential in naturally infected goats.

BACKGROUND Small ruminant lentiviruses escaping efficient serological detection are still circulating in Swiss goats in spite of a long eradication campaign that essentially eliminated clinical cases of caprine arthritis encephalitis in the country. This strongly suggests that the circulating viruses are avirulent for goats.To test this hypothesis, we isolated circulating viruses from naturally infected animals and tested the in vitro and in vivo characteristics of these field isolates. METHODS Viruses were isolated from primary macrophage cultures. The presence of lentiviruses in the culture supernatants was monitored by reverse transcriptase assay. Isolates were passaged in different cells and their cytopathogenic effects monitored by microscopy. Proviral load was quantified by real-time PCR using customized primer and probes. Statistical analysis comprised Analysis of Variance and Bonferroni Multiple Comparison Test. RESULTS The isolated viruses belonged to the small ruminant lentiviruses A4 subtype that appears to be prominent in Switzerland. The 4 isolates replicated very efficiently in macrophages, displaying heterogeneous phenotypes, with two isolates showing a pronounced cytopathogenicity for these cells. By contrast, all 4 isolates had a poor replication capacity in goat and sheep fibroblasts. The proviral loads in the peripheral blood and, in particular, in the mammary gland were surprisingly high compared to previous observations. Nevertheless, these viruses appear to be of low virulence for goats except for the mammary gland were histopathological changes were observed. CONCLUSIONS Small ruminant lentiviruses continue to circulate in Switzerland despite a long and expensive caprine arthritis encephalitis virus eradication campaign. We isolated 4 of these lentiviruses and confirmed their phylogenetic association with the prominent A4 subtype. The pathological and histopathological analysis of the infected animals supported the hypothesis that these A4 viruses are of low pathogenicity for goats, with, however, a caveat about the potentially detrimental effects on the mammary gland. Moreover, the high proviral load detected indicates that the immune system of the animals cannot control the infection and this, combined with the phenotypic plasticity observed in vitro, strongly argues in favour of a continuous and precise monitoring of these SRLV to avoid the risk of jeopardizing a long eradication campaign.

Wattles in goats are associated with the FMN1/GREM1 region on chromosome 10.

The presence of congenital appendages (wattles) on the throat of goats is supposed to be under genetic control with a dominant mode of inheritance. Wattles contain a cartilaginous core covered with normal skin resembling early stages of extremities. To map the dominant caprine wattles (W) locus, we collected samples of 174 goats with wattles and 167 goats without wattles from nine different Swiss goat breeds. The samples were genotyped with the 53k goat SNP chip for a subsequent genome-wide association study. We obtained a single strong association signal on chromosome 10 in a region containing functional candidate genes for limb development and outgrowth. We sequenced the whole genomes of an informative family trio containing an offspring without wattles and its heterozygous parents with wattles. In the associated goat chromosome 10 region, a total of 1055 SNPs and short indels perfectly co-segregate with the W allele. None of the variants were perfectly associated with the phenotype after analyzing the genome sequences of eight additional goats. We speculate that the causative mutation is located in one of the numerous gaps in the current version of the goat reference sequence and/or represents a larger structural variant which influences the expression of the FMN1 and/or GREM1 genes. Also, we cannot rule out possible genetic or allelic heterogeneity. Our genetic findings support earlier assumptions that wattles are rudimentary developed extremities.

Pyogranulomatous pneumonia in goats caused by an undescribed Porphyromonas species, "Porphyromonas katsikii".

A yet-undescribed bacterial species, tentatively named "Porphyromonas katsikii," was isolated from individuals of a small goat herd with pyogranulomatous pneumonia during an outbreak of acute respiratory disease. The isolated bacteria grew in the form of black-pigmented colonies after 14 days of incubation under anaerobic conditions at 37°C on a tryptic soy blood agar medium. The bacteria were identified as a yet-undescribed Porphyromonas species by determination of the nucleotide sequence of the rrs 16S rRNA gene, and this species was tentatively named Porphyromonas katsikii. PCR amplification with specific primers for this yet-undescribed species revealed the presence of P. katsikii in the lung tissue of all affected animals, while no PCR signals were evidenced from the lungs of healthy goats or from goats with pasteurellosis caused by Mannheimia haemolytica. These data indicate P. katsikii as the causative agent of acute respiratory distress. P. katsikii is phylogenetically related to Porphyromonas somerae and Porphyromonas levii, which cause pathologies in humans and animals, respectively. P. katsikii was not detected by PCR from samples of the gingival pockets or of the faces of healthy goats.

Representative Seroprevalences of Brucellosis in Humans and Livestock in Kyrgyzstan

Kyrgyzstan reported 77.5 new human brucellosis cases per 100,000 people in 2007, which is one of the highest incidences worldwide. In Kyrgyzstan, the currently used diagnostic tests in humans and animals are the Rose Bengal Test and the Huddleson test. A national representative cross-sectional study using cluster sampling proportional to size in humans, cattle, sheep, and goats was undertaken to assess the apparent seroprevalence in humans and animals. A total of 4,936 livestock sera and 1,774 human sera were tested in Naryn, Chuy, and Osh Oblasts. The overall apparent seroprevalences of brucellosis were 8.8% in humans (95% CI 4.5-16.5), 2.8% (95% CI 1.6-4.9%) in cattle, 3.3% (95% CI 1.5-6.9%) in sheep, and 2.5% (95% CI 1.4-4.5%) in goats. Naryn Oblast had the highest seroprevalences in humans and sheep. More men than women were seropositive (OR = 1.96; P < 0.001). Human seroprevalence was significantly associated with small ruminant seroprevalence but not with cattle seroprevalence. Annual incidence of human brucellosis exposure, measured by serological tests, was more than ten times higher than the annual incidence of reported clinical brucellosis cases. This indicates an under-reporting of human brucellosis cases, even if only a fraction of seropositive people have clinical symptoms. In conclusion, this study confirms the high seroprevalence of brucellosis in Kyrgyzstan and warrants rapid effective intervention, among others, by mass vaccination of sheep and goats but also of cattle.

Meningitis caused by Mycoplasma mycoides subspecies capri in a goat

A 2-year-old, female goat from Connecticut was submitted for necropsy with a 5-day history of pyrexia and intermittent neurologic signs, including nystagmus, seizures, and circling. Postmortem examination revealed suppurative meningitis. Histologic examination of the brain revealed that the meninges were diffusely infiltrated by moderate numbers of lymphocytes, macrophages, and fibrin, with scattered foci of dense neutrophilic infiltrate. Culture of pus and brainstem yielded typical mycoplasma colonies. DNA sequencing of the 16S ribosomal RNA gene revealed 99% sequence homology with Mycoplasma mycoides subspecies capri and Mycoplasma mycoides subspecies mycoides Large Colony biotype, which are genetically indistinguishable and likely to be combined as a single subspecies labeled M. mycoides subsp. capri. The present case is unusual in that not only are mycoplasma an uncommon cause of meningitis in animals, but additionally, in that all other reported cases of mycoplasma meningitis in goats, systemic lesions were also present. In the present case, meningitis was the only lesion, thus illustrating the need to consider mycoplasma as a differential diagnosis for meningitis in goats.

Management effects on colostrogenesis in small ruminants: a review

Colostrum feeding in small ruminants is crucial during the first hours after birth due to the lack of Ig transfer during pregnancy via the placenta. In addition the immature immune system of the neonate is slow to produce its own Ig during the first weeks of life. Colostrogenesis, i.e. the transfer of Ig from blood into mammary secretions, starts several weeks prepartum. In goat plasma, immunoglobulin G (IgG) concentration decreases by around 38% from the third month of gestation until partum, which coincides with the dry period. Thus, management during the dry period is crucial for the course of colostrogenesis. The colostrum synthesis is determined by the nutrition during the prepartum period, but the transfer of Ig is obviously independent of nutritional influences. The administration of conjugated linoleic acid during the dry period to dairy goats causes a less pronounced decrease of blood plasma IgG concentration (6%) but it did not change colostral IgG levels. In cattle, IgG1 is transported from blood into colostrum by an IgG1 specific receptor located on the surface of alveolar epithelial cells during colostrogenesis, and this is most likely similar in small ruminants. Via inactivation of this receptor, the Ig transfer is downregulated by increasing prolactin (PRL) during lactogenesis. It was recently observed in goats treated with PGF2 alpha, in order to induce parturition, lower colostrum IgG concentrations occurred concomitantly with an earlier increase of plasma PRL as compared to untreated animals. The effect of litter size and number of lactations on colostral IgG concentration in small ruminants has not been made fully clear until now most likely due to the different breeds used in the published studies.

Effect of the prolactin-release inhibitor quinagolide on lactating dairy cows

In most mammals, prolactin (PRL) is essential for maintaining lactation, and yet the short-term suppression of PRL during established lactation by bromocriptine has produced inconsistent effects on milk yield in cows and goats. To assess the effect of the long-term inhibition of PRL release in lactating dairy cows, 5 Holstein cows in early lactation received daily intramuscular injections of 1mg of the PRL-release inhibitor quinagolide for 9 wk. Four control cows received the vehicle (water) only. During the last week of the treatments, one udder half was milked once a day (1x) and the other twice a day (2x). Blood samples were harvested at milking in wk -1, 1, 4, and 8. The daily injections of quinagolide reduced milking-induced PRL release but not the basal PRL concentration. Quinagolide induced a faster decline in milk production, which was about 5.3 kg/d lower in the quinagolide-treated cows during the last 4 wk of treatment. During wk 9, the inhibition of milk production by quinagolide was maintained in the udder half that was milked 2x but not in the half milked 1x. Milk production was significantly correlated with the quantity of PRL released at milking. Quinagolide did not affect the release of oxytocin at milking. Serum concentration of insulin-like growth factor-1 was not affected by treatment or correlated with milk production. Serum concentrations of leptin and the calciotropic hormone stanniocalcin were not affected by the treatment. In conclusion, the chronic administration of the PRL-release inhibitor quinagolide decreases milk production in dairy cows. The effect is likely the result of the reduced release of milking-induced PRL and is modulated at the level of the gland by milking frequency.

A missense mutation in the skeletal muscle chloride channel 1 (CLCN1) as candidate causal mutation for congenital myotonia in a New Forest pony

A 7-month-old New Forest foal presented for episodes of recumbency and stiffness with myotonic discharges on electromyography. The observed phenotype resembled congenital myotonia caused by CLCN1 mutations in goats and humans. Mutation of the CLCN1 gene was considered as possible cause and mutation analysis was performed. The affected foal was homozygous for a missense mutation (c.1775A>C, p.D592A) located in a well conserved domain of the CLCN1 gene. The mutation showed a recessive mode of inheritance within the reported pony family. Therefore, this CLCN1 polymorphism is considered to be a possible cause of congenital myotonia.

Atypical scrapie isolates involve a uniform prion species with a complex molecular signature

The pathobiology of atypical scrapie, a prion disease affecting sheep and goats, is still poorly understood. In a previous study, we demonstrated that atypical scrapie affecting small ruminants in Switzerland differs in the neuroanatomical distribution of the pathological prion protein (PrP(d)). To investigate whether these differences depend on host-related vs. pathogen-related factors, we transmitted atypical scrapie to transgenic mice over-expressing the ovine prion protein (tg338). The clinical, neuropathological, and molecular phenotype of tg338 mice is similar between mice carrying the Swiss atypical scrapie isolates and the Nor98, an atypical scrapie isolate from Norway. Together with published data, our results suggest that atypical scrapie is caused by a uniform type of prion, and that the observed phenotypic differences in small ruminants are likely host-dependant. Strikingly, by using a refined SDS-PAGE technique, we established that the prominent proteinase K-resistant prion protein fragment in atypical scrapie consists of two separate, unglycosylated peptides with molecular masses of roughly 5 and 8 kDa. These findings show similarities to those for other prion diseases in animals and humans, and lay the groundwork for future comparative research.

Neuropathogenesis of naturally occurring encephalitis caused by Listeria monocytogenes in ruminants

Listeriosis is a serious food-borne disease with increasing frequency in humans and ruminants. Despite the facts that in both hosts, listeriosis can occur as rhombencephalitis and ruminants are a reservoir of Listeria monocytogenes (LM) strains pathogenic for humans, little work has been done on the pathogenesis in ruminants. This study investigates the neuropathogenesis of listeric encephalitis in over 200 natural cases in cattle, sheep and goats by analyzing anatomical distribution, severity, bacterial load and temporal evolution of the lesions. Our results suggest that LM gains access to the brainstem of all three species via axonal migration not only along the trigeminal nerve, but also along other nerves. The ensuing encephalitis does not remain restricted to the brainstem. Rather, LM spreads further from the brainstem into rostral brain regions likely by intracerebral axonal migration. Significant differences in severity of the lesions and bacterial load were found between cattle and small ruminants, which may be caused by species-specific properties of antibacterial immune responses. As histopathological lesions of human rhombencephalitis caused by LM strongly resemble those of ruminants, the disease likely has a similar pathogenesis in both hosts.