Field Trial Vaccination against Cowpox in Two Alpaca Herds.

In Europe, cowpox virus (CPXV) infection in South American camelids occurs as a so-called spill-over infection. Although infected animals generally have a mild form of the disease and survive, cases of fatal generalised CPXV infection have also been described. Prevention by prophylactic vaccination is the only way to protect animals from disease. In the present study, modified vaccinia virus Ankara (MVA) vaccine, which has been successfully used in many animal species, was used in a prime-boost vaccination regimen in two alpaca herds with a history of CPXV infection. The focus of the study was the prevention of further clinical cases, and to determine the safety and immunogenicity of the MVA vaccine in alpacas. The MVA vaccine was well tolerated and safe in the 94 animals vaccinated. An indirect immunofluorescence assay (IFA) using MVA as an antigen showed that the seroprevalence of antibody after booster vaccination was 81.3% in herd I and 91.7% in herd II. Detectable antibody titres declined to 15.6% in herd I and 45.8% in herd II over a 12-month period after booster vaccination. Animals could be divided into four groups based on individual antibody titres determined over one year: Group 1 consisted of 19.3% of animals that were seropositive until the end of the trial period; Group 2 consisted of 58.0% of animals that were seropositive after booster vaccination, but seronegative one year later; Group 3 consisted of 14.7% of animals that were not seropositive at any time point; and Group 4 consisted of 7.9% of animals that were seropositive after initial immunisation, seronegative six months later, but seropositive or intermediate in IFA one year after immunisation, likely because of natural exposure. In new-born crias born to MVA-vaccinated mares, specific maternal antibodies were detected in 50.0% of animals up to 14 weeks of age. Our results confirm that MVA vaccination is a feasible tool for the prevention of CPXV disease in alpacas. Long-term studies are needed to verify future vaccination regimen in CPXV affected herds.

[Clinical presentation of cowpox virus infection in South American camelids - A review]. / Klinisches Erscheinungsbild der Kuhpockenvirus-infektion bei Neuweltkameliden.

Cowpox virus (CPXV) infection is a reportable and potentially zoonotic disease that occurs sporadically in a variety of animals. During the past six decades, CPXV infection has been extensively researched and described in both domestic (cat, dog, horse, cattle) and zoo animals (e. g. elephant, rhinoceros, okapi). Of note, a review of the literature produced only three reports of CPXV in individual or small groups of South American camelids. The goal of this review was to describe the current knowledge as it relates to clinical features of CPXV infection in South American camelids and to compare the clinical manifestations with those described in other animal species. In alpacas and llamas, virus transmission occurs via direct contact with infected animals or oronasal infection through microlesions in the skin and mucous membranes. In its mild form, the disease is limited to certain regions of the body (head, neck, extremities or perineal region) and characterised by pustules or crusts. CPXV infection can also cause generalised and frequently lethal disease with multifocal to diffuse skin lesions (papules, pustules, crusts, ulcers) accompanied by virus replication in other organs. Conjunctivitis, stomatitis and rhinitis are seen commonly together with nonspecific clinical signs, including anorexia, listlessness and fever. As in other poxvirus infections, factors leading to an immunosuppression may contribute to the development of the clinical ma -nifestation of CPXV infection. There appear to be no specific manifestations of CPXV infection in South American camelids. More research is needed to fully understand the pathogenesis and epidemio logy of CPXV infection, particularly in South American camelids.

Epidemiological Investigations of Four Cowpox Virus Outbreaks in Alpaca Herds, Germany.

Four cowpox virus (CPXV) outbreaks occurred in unrelated alpaca herds in Eastern Germany during 2012-2017. All incidents were initially noticed due to severe, generalized, and finally lethal CPXV infections, which were confirmed by testing of tissue and serum samples. As CPXV-infection has been described in South American camelids (SACs) only three times, all four herds were investigated to gain a deeper understanding of CPXV epidemiology in alpacas. The different herds were investigated twice, and various samples (serum, swab samples, and crusts of suspicious pox lesions, feces) were taken to identify additionally infected animals. Serum was used to detect CPXV-specific antibodies by performing an indirect immunofluorescence assay (iIFA); swab samples, crusts, and feces were used for detection of CPXV-specific DNA in a real-time PCR. In total, 28 out of 107 animals could be identified as affected by CPXV, by iIFA and/or PCR. Herd seroprevalence ranged from 16.1% to 81.2%. To investigate the potential source of infection, wild small mammals were trapped around all alpaca herds. In two herds, CPXV-specific antibodies were found in the local rodent population. In the third herd, CPXV could be isolated from a common vole (Microtus arvalis) found drowned in a water bucket used to water the alpacas. Full genome sequencing and comparison with the genome of a CPXV from an alpaca from the same herd reveal 99.997% identity, providing further evidence that the common vole is a reservoir host and infection source of CPXV. Only in the remaining fourth herd, none of the trapped rodents were found to be CPXV-infected. Rodents, as ubiquitous reservoir hosts, in combination with increasingly popular alpacas, as susceptible species, suggest an enhanced risk of future zoonotic infections.