UPDATE

Since the eradication of smallpox, the most alarming developments have been the rise in the cases of genital molluscum contagiosum. It is believed that the prevalence of molluscum contagiosum has increased as an opportunistic infection due to the growing population of immunocompromised individuals(such as those with HIV disease).

Human monkeypox is a severe smallpox-like illness caused by monkeypox virus (MPV) which occurs in sporadic outbreaks. Infection is enzootic among squirrels and monkeys in the rainforests of western and central Africa . In 1996, cases of monkeypox were reported from villages in Zaire. The WHO and CDC investigated and found 511 monkeypox cases since February of that year. This monkeypox outbreak was the biggest recorded to date.

Vaccinia virus, that which proved so effective in the eradication of smallpox, allowed for a new approach to the development of vaccines. Now, widespread research is being conducted in which genes coding for the surface proteins of a given virus are inserted into the genome of an avirulent one. Thus, a live vaccine can be administered. The cells infected with the vaccine virus will make the surface proteins that will elicit a humoral and T-cell mediated immune response from the host.

Advantages of using vaccinia virus as the vector for cloned viral genes include:

Large genome which can allow for many gene insertions

Produced inexpensively

Relatively stable

Delivery by nonmedical persons

Cell-mediated immunity is elicited

However, some disadvantages include:

Rare serious side effects with regular vaccinia virus vaccine have been observed

Revaccination with vaccinia vector within 5 years may be unreliable

Rare complications can cause vaccinial rash, similar to smallpox.

A current debate is raging among scientists about whether the remaining stores of smallpox virus should be destroyed. With the ever-present threat of biological warfare, the discussions have intensified. If you would like to read some of the arguments in the debate, click here.

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