Buffalopox

Also known as

Buffalopox virus (BPXV)

Description

Buffalopox affects water buffalo (Bubalus bubalis)--the natural host--characterized by development of water-filled blisters that then turn into scabs on the teats and occasionally other sites. This virus will also infect cattle, with similar lesions, and humans. It occurs in India, Nepal, Bangladesh, Pakistan, Indonesia, Russia and Egypt. In water buffalo the disease is mainly seen in young and old animals.

The first recorded incidence was reported in water buffalo in India in 1934 but the virus causing the disease was not identified until 1977. Between 2006 and 2008, there were several outbreaks in domestic buffaloes in India. These buffaloes had lesions on udder, teats, limbs, around the ears and eyes, and hindquarters--indicative of a generalized rather than just a local infection.

In these cases, there was reduction of milk yield of about 30-35% which was followed by mastitis due to secondary bacterial infection. The milking attendants developed lesions on their chest, lower abdomen, fingers, hands, forearms, legs, shoulder-blade region, feet, and forehead and also had fever, swollen lymph nodes, and general discomfort. There was also evidence of milking attendants spreading the virus between individual buffalo and from buffalo to cattle.

Outbreaks of buffalopox or pox-like infections affecting buffalo, cows and humans have been recorded in many parts of the world with a large number of epidemics, but the generalized forms of the disease are now rare. Severe local forms of the disease (affecting the udder and teats, leading to mastitis) still occur, however.

This is a self-limiting disease with a course of two to three weeks but secondary bacterial infection may additional problems.

This disease occurs in two forms--mild and severe. Lesions are localized in the mild form whereas in the severe form, which is uncommon, the lesions are generalized and appear over many areas of the body. Secondary bacterial infection leads to infection of the ear, conjunctivitis (infection of the surface of the eye), and mastitis.

Lesions can occur on the udder, teats, and groin, over the salivary glands, and the base and inner surface of the ear and eyes. The severe form is now rare, and most cases seen today are mild. The end result is mainly high morbidity (many animals in the herd affected) and productivity loss.

When the virus infects milking animals it causes mastitis which reduces milk yield. In draft animals the disease hinders their working ability. Mastitis occurs in approximately half the infected animals; in severe cases, the reduction in milk production can be permanent. The incubation time in animals is about 2–4 days and in humans 3–19 days.

Humans in close contact with buffaloes are susceptible to buffalopox; with termination of smallpox vaccinations in 1980, humans no longer develop an antibody titer against the pox viruses and as a result have become more susceptible to viruses like buffalopox. Human-to-human transmission has not been reported. Milking of infected animals is one of the major ways the virus is spread; the people most at risk for contracting the disease are veterinarians, milk attendants, and other people in close proximity of infected animals.

Lesions usually occur on the teats of milking buffalo, but may also be present on the perineum (between anus and vulva or anus and scrotum), between the hind legs and around the eyes and ears, particularly of suckling calves. There is a typical progression of poxvirus infection through 5 stages, which include vesicular (blister), pustular and scab stages over a 14-day period, but this period may be prolonged by trauma during milking and by secondary infections.

The course of the clinical disease in cattle is not as long--usually less than seven days; this brief duration of the disease is possibly related to better immunity due to previous infection with cowpoxvirus, which is also an orthopoxvirus.

Diagnosis is made by observing the clinical signs and typical pock-like skin lesions and by laboratory confirmation of the virus.

Signs

• Stage 1 -diffuse redness on the skin;
• Stage 2– Papular stage (elevated hard areas on skin);
• Stage 3 –raised areas become blisters;
• Stage 4 – Pustular stage (pus formation);
• Stage 5 – crust or scab formation

Cause

The virus is classified in the family poxviridae under the genus Orthopox. Scientists are still debating whether it is a buffalo-adapted vaccinia virus (similar to cowpox that was used by Edward Jenner in 1798 for vaccination against human smallpox) or an original virus.

Buffalopox virus can be spread in several ways. Infection is often carried from animal to animal through close contact with lesions, and also by contaminated milkers’ hands, milking machines (teat cup) and mechanical transmission by biting flies such as sand flies and midges.

Prevention

Segregating affected animals (and any that have been in contact with them) from apparently healthy animals can help prevent spread of this disease. This also means using separate arrangements for milking the infected animals, with separate attendants.

Use of teat dips and antiseptic lotion can help, and any pox lesions can be cleaned with potassium permanganate to inactivate the virus and help keep it from spreading.

Treatment

There is no treatment that will help the animal overcome the virus any faster (the disease is self-limiting; the animal spontaneously recovers after a certain length of time) but topical application of antiseptic ointment like boric acid or broad spectrum antibiotic ointment on lesions can help curtail secondary bacterial infection.