October 23, 2018 UPDATE: OSAC is reissuing this report from 2017 in the midst of a new outbreak of monkeypox, a rare and potentially deadly disease that manifests in disfiguring skin lesions, and for which there is no treatment. Over 100 cases have already been confirmed, some of which have been fatal; according to the Nigeria Center for Disease Control, three cases were diagnosed in the UK and Israel in travelers with recent travel to Nigeria. The U.S. Embassy in Abuja has released a Health Alert, and the U.S. Centers for Disease Control & Prevention (CDC) have issued a Travel Notice on the outbreak as well. For more information on how monkeypox could affect travelers to Nigeria, please read this OSAC health snapshot.
October 25, 2017
As of October 20, the World Health Organization (WHO) was investigating 86 suspected cases of monkeypox in 11 states across Nigeria. The WHO Regional Laboratory in Senegal has so far confirmed three cases of monkeypox. While there has been one related suicide, there have been no disease-related deaths. Monkeypox is a rare disease that manifests in disfiguring skin lesions, and for which there is no treatment.
The Minister of Health is also working to discount circulating rumors, especially in Bayelsa state, that the military is intentionally spreading monkeypox through vaccinations. Contrary to these rumors, any vaccination efforts in Nigeria are undertaken by state governments and the federal Ministry of Health, not the military; additionally, no vaccine exists for the disease.
What is Breaking Out?
Monkeypox is a rare disease that is caused by infection with monkeypox virus, which belongs to the same genus as smallpox. The illness begins with fever, headache, muscle aches, backache, swollen lymph nodes, chills, and exhaustion. Within 1 to 3 days (sometimes longer) after presentation of fever, the patient develops a rash, often beginning on the face then spreading to other parts of the body. The illness typically lasts for 2−4 weeks.
There are two distinct genetic groups of the virus -- Central African (or Congo Basin) and West African – that do not geographic overlap geographically, as major rivers provide physical boundaries that prevent transmission between the potential carrier populations. West African monkeypox is associated with milder disease, fewer deaths, and limited human-to-human transmission. Case fatality in monkeypox outbreaks has been between 1% and 10%, with most deaths occurring in younger age groups.
The natural reservoir of monkeypox remains unknown; however, rodents are believed to play a role in transmission.
Where is it Breaking Out?
The first human case of monkeypox was recorded in 1970 in the Democratic Republic of Congo (DRC). The majority of cases have been reported in rural, rainforest regions of the Congo Basin and western Africa, particularly in the DRC, where it is considered endemic. Nigeria has had two previous instances of monkeypox: in 1971 (2 cases) and 1978 (1 case). A 2003 outbreak in the U.S. was the only instance of monkeypox infections in humans documented outside of Africa.
The current outbreak began in Yenagoa, Bayelsa state, on September 22. Only three monkeypox cases have been confirmed so far, all in Bayelsa. Suspected cases in the current outbreak have been reported in Akwa Ibom, Bayelsa, Cross River, Delta, Ekiti, Enugu, Imo, Lagos, Nasarawa, and Rivers states, and the Federal Capital Territory (see attached map). These states are mostly in the southern part of Nigeria. All four suspected cases in Lagos and both suspected cases in Abuja have been confirmed negative for monkeypox. There are no confirmed cases in either city. The Minister of Health said he expects that many of the suspected cases elsewhere are also not monkeypox but did not speculate further.
When Does it Occur?
There are three potential explanations for the most recent outbreak of monkeypox in southern Nigeria:
The Delta State Coordinator of the WHO, speaking in Abuja to the Association of Medical Scientists of Nigeria, suspected the outbreak was exacerbated by regional flooding. He posited that “floodwater was a major source of infectious communicable diseases because animals defecate in floodwater, which humans come in contact with.” Specifically, he suggested: “For floods…lasting for one to four weeks, expect rodent-borne diseases...” The National Coordinator of the NCDC identified flood-prone areas as Rivers, Benue, and Niger states, and the coastal areas of Akwa Ibom, Adamawa, Bayelsa, Cross River, Jigawa, Kaduna, and Lagos states, many of which overlap with the current monkeypox outbreak .
Another theory is that humans may have been exposed to multiple infected monkeys or rodents across a broad geographic area.
A final theory is that since the eradication of smallpox and the cessation of vaccination programs, populations in areas prone to pox outbreaks may have a decreased immunity, allowing Orthopox viruses such as monkeypox to infect people.
Who is Impacted?
Transmission of monkeypox virus occurs when a person comes into contact with the virus from an animal, human, or material contaminated with the virus. The virus enters the body through broken skin (even if not visible), respiratory tract, or the mucous membranes.
Animal-to-human transmission may occur by bite or scratch, bush meat preparation, direct contact with body fluids or lesion material, or indirect contact with lesion material. In Africa, human infections have been documented through the handling of infected monkeys or rodents, with the latter being the major reservoir of the virus. Eating inadequately cooked meat of infected animals is a possible risk factor.
Human-to-human transmission is thought to occur primarily through large respiratory droplets-- sneezing. However, transmission would require close and prolonged contact. Other human-to-human methods of transmission include direct contact with body fluids or lesion material or indirect contact with lesion material (ie. contaminated clothing or linens). Human-to-human transmission is has only been documented in the Central African strain of monkeypox. Still, precautions are needed to mitigate the potential human-to-human transmission. The Minister of Health advised that “Health care workers are strongly advised to always practice universal precautions while handling patients and/or body fluids at all times. They are also urged to be alert, be familiar with the symptoms of monkey pox and maintain a high index of suspicion.”
Why Should I be Concerned?
Monkeypox is a very rare disease. This current outbreak seems to be the West Africa strain, for which human-to-human transmission has not been documented, underscoring that the case load is likely to remain relatively low. There is no treatment or vaccine available.
Monkeypox is self-limiting, meaning that it generally resolves without treatment. Monkeypox is in the same genus as smallpox, so those who received the smallpox vaccine are likely protected from getting monkeypox or are more likely to have a less severe case. Past data from Africa suggests that having received the smallpox vaccine is at least 85% effective in preventing monkeypox. Smallpox, however, was eradicated in the 1980s, so routine vaccination against smallpox among the general public was stopped because it was no longer needed.
How do I Respond?
In an effort to raise awareness on the risk factors, the National Youth Council of Nigeria announced a nationwide campaign, “Kick Monkey pox out of Nigeria,” on October 23. The program will address prevention measures, vaccinations, and fear reduction.
The WHO is supporting Bayelsa state in rumor control efforts, contact tracing, and containment of any further spread of the disease.
During human-to-human monkeypox outbreaks, close contact with other patients is the most significant risk factor for monkeypox infection. According to the U.S. Centers for Disease Control and Prevention (CDC), there are number of measures that can be taken to prevent infection with monkeypox virus:
Avoid contact with animals that could harbor the virus (including animals that are sick or that have been found dead in areas where monkeypox occurs).
Avoid contact with any materials, such as bedding, that has been in contact with a sick animal.
Isolate infected patients from others who could be at risk for infection.
Practice good hand hygiene after contact with infected animals or humans. For example, washing your hands with soap and water or using an alcohol-based hand sanitizer.
Use personal protective equipment when caring for patients.
WHO Monkeypox Sheet