Animal poxvirus - Molecular diagnosis (PCR); Molecular identification (PCR and sequencing).
Parapoxvirus: Pseudocowpox virus (paravaccinia) -PCPV-, Orf virus -ORFV-,
Bovine papular stomatitis virus (Bovine Papular Stomatitis BPSV-virus), Parapoxvirus of Red Deer in New Zealand (PVNZ)
Orthopoxvirus: cowpox (CPXV), Vaccinia virus (VACV) and
Monkeypox virus (MPXV)
The Parapoxvirus (PPV) and orthopoxvirus (OPV) are two kinds of viruses included in the family Poxviridae. This family of viruses is composed of large viruses with double - stranded DNA (dsDNA) genome. Most of them, except the species Variola virus (VARV) which had as its only host the man, cause infections in animals and may occasionally be transmitted to humans. The smallpox virus caused the last case in 1977, and officially considered eradicated from the world since the 1980 declaration of the 33rd Assembly of the World Health Organization, remaining preserved strains only in the CDC (Center for Disease Control) Atlanta, Georgia US and the State Research Center of Virology and Biotechnology, Novosibirsk in Russia.
Four species in this genus of viruses that cause skin disease, proliferative, located in domestic and wild ruminants include:
• Orf Virus (ORFV).
• Pseudocowpox virus (PCPV).
• Papular Stomatitis Virus Bovina (BPSV: Bovine Papular Stomatitis virus).
• Parapoxvirus of Red Deer in New Zealand (PVNZ).
All species are related to infections in ruminants, and the first three (ORFV, PCPV and BPSV) can cause skin infections in humans, causing a similar injury, it is clinically difficult to know the cause of the injury.
They are eruptive epitheliotropic virus Universal distribution, causing no systemic skin diseases localized), vesicular and in domestic and wild ruminants, although they have a narrow range of hosts occasionally be transmitted to humans, causing localized mainly in the hands injuries, generally professional, affecting milkers, or others in contact with infected animals, as with milkers nodules (nodule or Pseudocowpox Milker's). In general, infection occurs through scarified or damaged, which allows virus replication in keratinocytes near the entry point, with a clinical course characterized by the steps of maculae, papules, vesicles, pustules and scabs skin. It may be vesicles and pustules injuries covered by scabs. In the absence of bacterial contamination, or other complication, the scabs fall off after a few days, and heals quickly.
Farmers, milkers, and develop closer contacts lesions on the hands, forearms, legs and face, along with some accompanying systemic symptoms. However, unlike those caused by infections Orthopoxvrus (OPV) that cause systemic or localized infections, infections Parapoxvirus (PPV) usually benign, self - limited and localized. Also, they do not produce long - lasting immunity.
The infectious bovine papular stomatitis (BPSV) usually affects calves, presenting papules, slightly erosive, mainly in the nose, lips, oral mucosa and hard palate and in cow udders. In people, it is associated with nodules and pustules on the hands or face.
The Pseudocowpox (PCPV) virus enters flocks through infected animals, slowly spreading among them, by direct or indirect contact.
The Orf (contagious pustular dermatitis) virus preferentially affects sheep and goats, in which oral or perioral provoked lesions. In people it causes vesicles and nodules on hands or face, or hyperplastic nodules accompanied by lymphadenopathy.
Several species in this genus of viruses that cause systemic disease or localized cutaneous having as hosts to people, non - human primates, ruminants, rodents and felines, etc. are included.
• Human Pathogen:
• Variola virus (VARV), which causes Smallpox (Smallpox), now eradicated from the world, and only preserved in a center in the US Russia and elsewhere.
• Pathogens animals with economic importance veterinary and public health for its zoonotic importance.
• monkeypox virus (MPXV)
• cowpox virus (CPXV)
• Vaccinia Virus (VACV)
• Virus horsepox (HSPV)
• Virus buffalopox (BPXV)
• Virus camelpox (VSMC)
• Virus Ectromelia (TVET)
The ways to make their diagnosis and identification has changed radically in recent years. Conventional methods were based on slow procedures requiring specific antisera, available only in some specialized centers in poxviruses, and not accessible to all laboratories, and virus culture, with its implicit risks for handling. These methods were: isolation and virus neutralization with specific antisera; hemagglutination inhibition; plaque morphology in cell culture or pustules chorioallantoic membrane or chicken embryo; capacity of cells inoculated cell cultures hemadsorber erythrocytes; temperature replication in cell culture or in chorioallantoic membrane chicken embryo; Analysis of viral proteins by polyacrylamide gel electrophoresis.
Currently, molecular methods as restriction endonuclease profile and nucleotide sequencing after PCR amplification, have become the most useful methods. These methods eliminate the need to first grow the virus in the laboratory, with consequent advantages.
Viruses capable of infecting man now, one of them, cowpox (CPXV) is considered an emerging pathogen, cases are occurring. Another implies a health risk to which we must be prepared: monkeypox virus (MPXV). Finally, another problem is causing some countries: Vaccinia (VACV) virus.
Cowpox virus (CPXV): this virus but can think by name which mainly affects cattle, is not, and is more fully Poxvirus of hosts. Its natural reservoir are wild rodents (bank vole, wood mouse, ...), and cows, cats, and other captive animals are only an accidental host. Transmission most common people is through direct contact with infected rodents, as some rats as pets (Rattus norvegicus) ( "Fancy Rats"), or cats or other animals that may have been infected with rodents, such as animals captive zoo or other purposes (circuses). This virus infections are generally localized and self - limiting, but may be more severe in people affected dermatitis, eczema or immunosuppressed. In France and Germany, between December 2008 and January 2009, there was an outbreak with 12 cases in France and 18 cases in Germany.
The increase in HIV infections, may be motivated by the lack of cross protection conferred by previous smallpox vaccination inadvisable since declared eradicated disease.
In people generally infection manifests as an erythematous, inflamed circumscribed lesion that develops into central necrosis with swollen edges, painful, approximately 1.5 cm in diameter, and sometimes accompanied by lymphangitis regional lymphadenopathy. Its onset and intensity is related to the history of vaccination against smallpox, so when it occurs in a non - vaccinated person the incubation period is shorter (3-5 days), whereas if the period occurs in a vaccinee incubation is longer, the clinic is less intense, without fever, without lymphadenopathy. In many cases, sometimes in the form of family outbreaks, there is epidemiological history of acquiring a pet (Rattus norvegicus) who died a few days after acquisition, after presenting cough and eye hemorrhagic lesions within a few days of his acquisition.
The effectiveness of cross-smallpox vaccine protection, makes US vaccination is recommended for those who may be exposed to cowpox, and researchers.
Monkeypox virus (MPXV): This virus also has as a reservoir for several species of rodents or squirrels that live in rain forests of Central Africa, and can affect non - human primates and humans, cases having occurred in the US as a result of contact with an infected animal. His clinic reminds produced by human smallpox (smallpox) due to Variola (VARV) virus. In general, after an incubation period of about 2 weeks, a fever followed by generalized rash it appears. The infection can be transmitted person to person and can be fatal with a mortality rate of 0 to 10% of cases compared with 10-30% of smallpox. After discontinuing the vaccination against smallpox, there is less protection against this virus.
Vaccinia virus-like (VACV) in Brazil are occurring outbreaks of infection by a virus similar to vaccinia virus. Vaccinia virus is admitted that it was used by Edgard Jenner when he published his proposal "An I inquired Into the Causes and Effects of the Variolae-Vaccine or cowpox" (1798). According to this description seems like the cowpox the used virus, but today you have questions, having thought a Pseudocowpox was used, and even have evidence that in the nineteenth century, was using a horsepox virus for their minor side effects.
Treatment of orthopoxvirus infections, Parapoxvirus and Molluscipoxvirus
Of the various alternatives have been proposed, cidofovir, accepted by the FDA for the treatment of cytomegalovirus retinitis since 1996, is considered the most active alternative to orthopoxvirus infections, Parapoxvirus and Molluscipoxvirus (Molluscum contagiosum virus).
Tests in IVAMI.
• molecular diagnostics using PCR Semi genes, followed by sequencing of amplicons for confirmation.
Type of sample:
• Exudate or scraping of the skin lesions of animals suspected of having the infection, or suspected lesions by contact with potential animal reservoirs (rodents) or transmitters (cats, cows, captive animals, ..).
Preservation and shipment of sample:
Refrigerated (preferred) for less than 2 days.
Frozen: over 2 days.
Cost of the test: