Cowpox virus infection of cynomolgus macaques as a model of hemorrhagic smallpox.

Hemorrhagic smallpox was a rare but severe manifestation of variola virus infection that resulted in nearly 100% mortality. Here we describe intravenous (IV) inoculation of cowpox virus Brighton Red strain in cynomolgus macaques (Macaca fascicularis) which resulted in disease similar in presentation to hemorrhagic smallpox in humans. IV inoculation of macaques resulted in a uniformly lethal disease within 12 days post-inoculation in two independent experiments. Clinical observations and hematological and histopathological findings support hemorrhagic disease. Cowpox virus replicated to high levels in blood (8.0-9.0 log(10) gene copies/mL) and tissues including lymph nodes, thymus, spleen, bone marrow, and lungs. This unique model of hemorrhagic orthopoxvirus infection provides an accessible means to further study orthopoxvirus pathogenesis and to identify virus-specific and nonspecific therapies. Such studies will serve to complement the existing nonhuman primate models of more classical poxviral disease.

Species interactions in a parasite community drive infection risk in a wildlife population.

Most hosts, including humans, are simultaneously or sequentially infected with several parasites. A key question is whether patterns of coinfection arise because infection by one parasite species affects susceptibility to others or because of inherent differences between hosts. We used time-series data from individual hosts in natural populations to analyze patterns of infection risk for a microparasite community, detecting large positive and negative effects of other infections. Patterns remain once variations in host susceptibility and exposure are accounted for. Indeed, effects are typically of greater magnitude, and explain more variation in infection risk, than the effects associated with host and environmental factors more commonly considered in disease studies. We highlight the danger of mistaken inference when considering parasite species in isolation rather than parasite communities.

Host condition and individual risk of cowpox virus infection in natural animal populations: cause or effect?

Recent studies have provided evidence that endemic pathogens may affect dynamics in animals. However, such studies have not typically considered that infected individuals might have a preceding underlying poor condition. We examined whether individuals in poor condition are more likely to become infected by an endemic pathogen, using as a system the dynamics of cowpox virus in field voles. With data from monthly sampled vole populations, a nested case-control study evaluated whether susceptible individuals with poorer condition had higher probabilities of contracting cowpox. The influence of condition was found to be considerable, especially for males. At times when a susceptible male with good body condition had a relatively low probability of becoming infected, a susceptible male with poor body condition was twice as likely to contract cowpox; if this male was also anaemic, the chances were almost quadrupled. We discuss the care needed when interpreting the findings of wildlife disease studies.

Concurrent infection of a cat with cowpox virus and feline parvovirus.

Concurrent infection with cowpox and feline parvovirus was diagnosed in a 5-month-old male European Short Hair cat. Microscopical examination of the facial skin, ears and foot pads revealed multifocal to coalescing, ulcerative to necrotizing dermatitis and panniculitis with ballooning epidermal degeneration and eosinophilic cytoplasmic inclusion bodies. Immunohistochemistry, polymerase chain reaction testing and virus isolation confirmed infection with a strain of cowpox virus similar to that isolated from a cat in Germany 5 years previously. Lymphoid tissues were depleted and there was catarrhal enteritis caused by feline parvovirus as confirmed by immunohistochemistry and in-situ hybridization. This co-infection did not result in a more severe and rapid course of the poxvirus-associated disease.

Cowpox virus infection associated with a streptococcal septicaemia in a foal.

Cowpox virus infection associated with a streptococcal septicaemia was diagnosed in a weak German Warmblood filly, born 29 days prematurely, and humanely destroyed on the sixth day of life. At necropsy, ulcerative lesions in the alimentary tract, colitis, polyarthritis and nephritis were observed. Transmission electron microscopical examination of specimens from ulcerative lesions revealed typical orthopox virions. Cowpox virus was unequivocally identified by virological and molecular-biological methods.

[Localized cowpox/cat pox virus infection. Aspects of epidemiology, diagnosis and therapy]. / Lokalisierte Infektion mit dem Kuhpocken-/Katzenpockenvirus. Aktuelles zur Epidemiologie, Diagnostik und Therapie.

Only few human cowpox/catpox infections have been reported until now. The diagnosis of bland localized infections may be missed, if this disease is not well known. However, early diagnosis of localized cowpox/catpox infections is important, since at least immunocompromised patients are at risk of potential lethal generalization similar to generalized variola vera. Using a typical case report, the characteristics of the disease, as well as the current aspects of epidemiology, diagnosis and therapy are summarized. The characteristic finding of intracytoplasmatic inclusion bodies by light microscopy can be demonstrated in a human biopsy-specimen for the first time and greatly facilitated the diagnosis.

Cowpox infection causing a generalized eruption in a patient with atopic dermatitis.

We report a patient with a history of atopic dermatitis who developed a generalized eruption due to cowpox infection. The infection was probably acquired from the patient's cat. This is the first report from Britain of cowpox causing Kaposi's varicelliform eruption in a patient with atopic dermatitis.