For the second time in 2016 we are seeing reports of an outbreak of Monkeypox in the Central African Republic. The first outbreak, which started in late December of 2015, was reported in early January (see Monkeypox Outbreak Reported In Central African Republic), and was followed a month later Reports Of A Large Monkeypox Outbreak In The DRC.
If it seems as if we are seeing more frequent outbreaks in recent years, there is some evidence to back that up.
A 2016 study (see EID Journal:Extended H-2-H Transmission during a Monkeypox Outbreak) looked at a large 2013 outbreak of Monkeypox in the DRC and suggests that the virus's epidemiological characteristics may be changing (possibly due to the waning smallpox vaccine derived immunity in the community).
In 2013, the DRC reported a 600% increase in cases over both 2011, and 2012. The authors also cite a higher attack rate, longer chains of infection, and more pronounced community spread than have earlier reports.
First a report from Reliefweb.int on this latest outbreak, then I'll return with more.
Basse-Kotto prefecture / Sub-prefecture of Mingala
Health: An epidemic of smallpox Monkey (Monkey Pox) was reported in four villages in the Sub-prefecture of Mingala. According to the National Health Cluster, the first case was recorded August 17, 2016, and 14 cases with 1 death were reported on 15 September. According to the same source, 10 cases of unsolved deaths were reported by the community during the same period in these villages.
Some cases are supported at the health post Irra Banda (about 50 km from Mingala, Bria Mingala-axis), while others are referred to the District Alindao hospital. A consultation is underway in Bangui, between the Ministry of Health and health sector partners, to respond to this epidemic through communication activities, capacity building and staffing support for inputs . At Alindao, health partner has initiated outreach activities in villages in the sub-prefecture of Mingala.
Recall that a first outbreak in the Prefecture of Mbomou (and Bakouma Bangassou), was declared December 29, 2015 by the Ministry of Health. The latter was supported by end January 2016.
Human monkeypox was first identified in 1970 in the DRC, and since then has sparked small, sporadic outbreaks in the Congo Basin and Western Africa.
The name `monkeypox’ is a bit of a misnomer. It was first detected (in 1958) in laboratory monkeys, but further research has revealed its host to be rodents or possibly squirrels.
It produces a remarkably `smallpox looking' illness in humans, albeit not as deadly. The CDC's Monkeypox website states:
The illness typically lasts for 2−4 weeks. In Africa, monkeypox has been shown to cause death in as many as 1 in 10 persons who contract the disease
Humans can contract it in the wild from an animal bite or direct contact with the infected animal’s blood, body fluids, or lesions, but consumption of under cooked bushmeat is also suspected as an infection risk.
Human-to-human transmission is also possible. This from the CDC’s Factsheet on Monkeypox:
The disease also can be spread from person to person, but it is much less infectious than smallpox. The virus is thought to be transmitted by large respiratory droplets during direct and prolonged face-to-face contact. In addition, monkeypox can be spread by direct contact with body fluids of an infected person or with virus-contaminated objects, such as bedding or clothing.
According to the CDC there are two distinct genetic groups (clades) of monkeypox virus—Central African and West African. West African monkeypox is associated with milder disease, fewer deaths, and limited human-to-human transmission.
Somewhat famously, the United States saw an outbreak (of the milder, West African clade) in 2003 that affected 47 confirmed and probable cases across six states—Illinois, Indiana, Kansas, Missouri, Ohio, and Wisconsin - all of whom had contact with infected prairie dogs purchased as pets.
These pets became infected when an animal distributor imported hundreds of small animals from Ghana, which in turn infected prairie dogs that were subsequently sold to the public (see MMWR Update On Monkeypox 2003).
While still considered a geographically limited threat, in 2010 a study that appeared in PNAS warned that the incidence of human monkeypox infection was increasing, and that it posed a potential risk well beyond localized outbreaks in Africa.
Although monkeypox outbreaks tend to burn themselves out fairly quickly, and rarely spread very far, those were the same qualities we attributed to Ebola two years ago. So we'll keep an eye on this outbreak, in the unlikely event it should spread beyond Mingala.