Monkeypox: Surveillance needed of high risk groups, not the entire population

Close on the heels of Covid-19 pandemic, which experts are convinced is not yet over, the spectre of monkeypox has started playing havoc with our psyche. Hyperbolic TV channels have helped cause alarm and the government has asked ports and airports to strictly screen international passengers. It is not clear what they expect to find since it apparently takes three weeks for the symptoms of monkeypox to manifest.

The name Monkeypox itself is a misnomer. The name has its origins in the discovery of the condition in captive Asiatic monkeys in Copenhagen in 1958. The virus survives in nature among small animals like squirrels.

Monkeypox virus belongs to the same family as the smallpox virus. Fortunately, while the eruptions have some resemblance to smallpox, monkeypox is a poor cousin. It is mild and self-limiting with case fatality rates varying between 0-10% in Africa, which tends to move towards zero outside Africa, perhaps due to better nutrition and access to healthcare.

The symptoms are fever, muscle pain, swollen glands and rashes, which have to be differentiated from chickenpox, and other cases of fever with rashes. Human to human transmission is by intimate contact while respiratory transmission is possible, but not very efficient. The course of the illness is 2-4 weeks. Smallpox in contrast had a case fatality rate of over 30%.

The smallpox endgame in the 1970s unearthed cases of monkeypox in Africa. During smallpox eradication campaign surveillance activities were intensified. This revealed scattered cases of monkeypox in that continent.

In the 1980s, WHO carried out serologic and virologic studies in Congo. Antibodies were detected in very few monkeys. Antibodies were found in Gambian rats and elephant shrews. Three-fourth of the human cases were children due to intimate contact with animals or due to handling their carcasses. The secondary attack was 8% to 9% within household contacts. The case fatality rate in the African continent ranged from zero to 10%, the Western African strain being less lethal than the Congo strain.

In 2003, monkeypox infection of humans was identified in the US. This was traced to prairie dogs that were infected from African small mammals imported as exotic pets. Gambian rat, rope squirrel and dormouse from the African shipment of exotic species originating in Ghana were implicated.

The biggest ever outbreak of monkey pox outside the African continent began in May 2022. By midJuly 2022, over 14,000 cases have been reported from 70 countries.

The European Union together with UK has reported 6,892 cases by first week of July. Majority of cases (42%), were aged between 31 to 40 years, and interestingly, 99.5% were males. Only around 10% needed hospitalisation, and only three needed ICU admission.

Interestingly 43% of those affected were HIV positive, and around half had history of other sexually transmitted infections in the past [Allied Forces!]. There were no deaths. Only 0.33% of the cases were healthcare workers. None died. Genomic studies indicated that the less virulent West African strain was responsible for the outbreak.

In the UK which had more detailed data, 97% of the cases were homosexual or bisexual men. Of these, 54% had history of other sexually transmitted infections, and 31.8% had 10 or more sexual partners in the last three months (surely some moderation is called for!).

Preventive strategy: Beyond Africa, monkeypox is behaving like a sexually transmitted infection. Therefore, promoting use of condoms in high-risk groups appears to be a clear priority.

Two cases have been reported in India at the time of writing. With our experience in HIV control we can take on monkeypox surveillance among the high-risk population as for HIV and with the same infrastructure. A self-limiting disease with almost zero mortality in the healthy with access to healthcare should not be cause for panic or stigma.

Modified smallpox vaccine is being recommended for monkey pox.

(The author headed the mobile epidemic team of the Armed Forces. He heads Deptt of Community Medicine, DY Patil Medical College, Pune)

(This was first published in National Herald on Sunday)