WHO: Monkeypox In The DRC

Credit WHO

#14,263


One tends not to worry about the creek rising when their house is already on fire, so we've heard relatively little about the DRC's other ongoing epidemics during their year-long battle with Ebola. 

But the WHO AFRO weekly Outbreaks and Emergencies Bulletin currently lists 4 other disease outbreaks, in addition to their ongoing humanitarian crisis;  Cholera, Measles, Monkeypox, and Poliomyelitis (cVDPV2).

The latest Monkeypox summary reads:

Since the beginning of 2019, a cumulative total of 3 015 monkeypox cases, including 64 deaths (CFR 2.1%) were reported from 111 health zones in 16 provinces. In week 29 (week ending 21 July 2019), 112 cases and one death were reported nationally. Sankuru province reported 63% of cases during the reporting week.

While there is no mention of how many of these are `confirmed cases', 3000+ suspected or probable cases in just over 6 months is worthy of our attention.

The name `monkeypox’ is a bit of a misnomer. It was first detected (in 1958) in laboratory monkeys, but further research has revealed its primary hosts to be rodents or possibly squirrels.

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 monkeypox was first identified in 1970 in the DRC, and since then has sparked small, sporadic outbreaks in the Congo Basin and Western Africa. 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.

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 - which has been spreading recently in Nigeria - is associated with milder disease, fewer deaths, and limited human-to-human transmission.

The more severe form of Monkeypox is most commonly found in the Central Africa countries of the DRC and the CAR - where outbreaks have been on the rise for years - presumably because smallpox vaccinations (which provided up to 85% protection) were halted in the late 1970s.

As the percentage of vaccinated members of the community dwindles, the risks of outbreaks are only expected to increase (see 2010 PNAS study Major increase in human monkeypox incidence 30 years after smallpox vaccination campaigns cease in the Democratic Republic of Congo).
 
Routine vaccination against smallpox ended in the United States in 1972, and worldwide by the end of that decade. Today more than half of the world's population is unvaccinated, and the level of protection remaining among those vaccinated 50+ years ago is highly suspect.

All of which makes the potential evolution and spread of monkeypox of growing international concern.

In 2013, the DRC reported a 600% increase in cases over both 2011, and 2012 (see EID Journal:Extended H-2-H Transmission during a Monkeypox Outbreak) . The authors also cite a higher attack rate, longer chains of infection, and more pronounced community spread than have earlier reports.

Like all viruses, Monkeypox continues to evolve and diversify, as discussed in the 2014 EID Journal article Genomic Variability of Monkeypox Virus among Humans, Democratic Republic of the Congo, where the authors cautioned:

Small genetic changes could favor adaptation to a human host, and this potential is greatest for pathogens with moderate transmission rates (such as MPXV) (40). The ability to spread rapidly and efficiently from human to human could enhance spread by travelers to new regions.

Although monkeypox is normally restricted to small outbreaks in Africa, in 2003 we saw a rare outbreak in the United States when a Texas 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).

By the time that outbreak was quashed, the U.S. saw 37 confirmed, 12 probable, and 22 suspected human cases. Among the confirmed cases 5 were categorized as being severely ill, while 9 were hospitalized for > 48 hrs; although no patients died (cite).

Nigeria saw its first Monkeypox outbreak in nearly 40 years in the fall of 2017, while last September the UK saw two imported cases from Nigeria (see  Eurosurveillance Rapid Comms: Two cases of Monkeypox imported to the UK) and a month later Israel: MOH Confirmed An Imported Monkeypox Case).

And in May of this year (see Singapore MOH: 1st Imported Case Of Monkeypox (ex Nigeria), we saw yet another exported case. 

While exported cases have been rare, these examples show how easily Monkeypox can turn up in non-endemic areas, and potentially spread.

Nearly 4 months ago, in CDC: The 8 Zoonotic Diseases Of Most Concern In The United States, we looked at a newly published One Health Zoonotic Disease Prioritization report, that characterized and ranked 56 zoonotic threats to the United States based on potential impact and likelihood of occurring.

The 8 zoonotic diseases of most concern in the U.S. were:

• Zoonotic influenza
• Salmonellosis
• West Nile virus
• Plague
• Emerging coronaviruses (e.g., severe acute respiratory syndrome and Middle East respiratory syndrome)
• Rabies
• Brucellosis
• Lyme disease

But also on that list Ebola came in as #16,  Crimean-Congo Hemorrhagic Fever landed 15th,  Nipah was 20th, and Monkeypox was 29th. As outbreaks ebb and flow around the world, it is likely that these rankings will change over time. 

The Monkeypox virus - particularly the Central African clade - represents a genuine public health concern, albeit not as horrific as the tabloid press would have us believe.

For additional reading, a couple more on-topic studies include:

MMWR: Emergence of Monkeypox — West and Central Africa, 1970–2017

The Lancet: Genomic Characterisation Of Human Monkeypox Virus In Nigeria