The Nigerian Centre for Disease Control (NCDC) confirmed three cases of monkeypox today among dozens of suspected cases.
The samples were sent to Dakar, Senegal, for laboratory analysis at the World Health Organization (WHO) Regional Laboratory last week, and the positive results shed new light on what could be one of the largest monkeypox outbreaks in Africa.
However, a global health expert who has worked on vaccination campaigns and investigated outbreaks in Africa over the past decades said some of the features of the current outbreak don't fit the typical pattern and that local health officials face complex challenges in protecting people against the disease.
Confirmed cases are from one state
Since Sep 22, there have been 60 reports of suspected monkeypox cases from across Nigeria. The laboratory analysis showed that 12 suspected cases from the Bayelsa state were not positive for monkeypox. The NCDC said that all patients with suspected and confirmed monkeypox are currently receiving supportive medical care and improving.
The NCDC offered no further details on the confirmed cases, besides noting that they were from Bayelsa state. The agency said the likely source of infection is through primary zoonotic transmission, and cautioned Nigerians to avoid contact with squirrels, rats, and any animals that appear sick.
"It is important to note that there has been no confirmation of Monkeypox in any other part of the country, and it is likely that many of the other cases being reported are not caused by the Monkeypox virus," the NCDC said today. "Nigerians should continue to be vigilant at all times."
Monekypox is a virus related to smallpox. It's extremely rare and usually kills 1 of every 10 infected. There is no cure for the disease, but the smallpox vaccine has been used prophylactically in small outbreak settings.
Expert cautions to wait for more confirmation
Joel Breman, MD, a consultant for the US National Institutes of Health Fogarty Institute, said that while monkeypox is a clinically striking disease, other illnesses, including severe chickenpox, can mask themselves as the virus.
"Typically you don't see monkeypox so spread out across a country," said Breman in an interview. "For seven states to report all these cases in 3 weeks is odd. There have been so many calls for diseases that look like monkeypox or smallpox, but turn out not to be. "
Human monkeypox was first detected in 1970. There have been scattered cases throughout Africa and Asia since then, with Nigeria reporting 3 cases in the mid 1970s. The incubation period for human illness with the virus is usually 10 to 14 days, with accompanying fever, headache, and swollen lymph nodes, as well as a pox-like rash.
Breman, who spent years in Africa first conducting smallpox vaccination campaigns and later investigating Ebola, said there has never been such a large monkeypox outbreak, but the changing demographics of Africa could be making people more susceptible to the disease. As urban populations have boomed, more Africans are living in proximity to jungles and hunting areas where the virus usually dwells.
Moreover, it's been 35 years or more since smallpox was eradicated, leaving current young adults and children free from any immunity to monkeypox the smallpox vaccine may afford.
"All vaccination was stopped by 1984 at the latest, and we may be seeing waning coverage even in those vaccinated," said Breman, who said that while it's too early to assume Nigeria is experiencing widespread monkeypox, the government should take steps to protect their citizens.
"Maybe, unless you have a smallpox scar on your arm, you don't treat someone with suspected monkeypox," Bremen said.
As for how and if the smallpox vaccine could be used in case of a wider outbreak of the disease, Breman said the WHO keeps some stores of the vaccine on hand, but determining who to vaccinate would depend on age, transmission, and origin of the outbreak.
Oct 16 NCDC update