Outbreak News

Central African Republic: 34 cases have been reported, including two deaths.

Republic of Congo: Nine total cases have been reported with no fatalities.

Democratic Republic of the Congo: 824 total cases have been reported, including 12 deaths.

Nigeria:  311 cases (132 confirmed) and seven fatalities have been recorded.

 

 

WHO

Monkeypox – Cameroon

 

CBN

“…..In September 2017, the Nigeria Centre for Disease Control (NCDC) was notified of an 11-year-old boy with monkeypox. The source of the disease was unclear, though the boy and 2 of his siblings had played with a neighbor’s monkey (which was not ill). A total of 5 other members of the index patient’s household developed similar symptoms……”

WHO

Key facts

• Monkeypox is a rare disease that occurs primarily in remote parts of Central and West Africa, near tropical rainforests.
• The monkeypox virus can cause a fatal illness in humans and, although it is similar to human smallpox which has been eradicated, it is much milder.
• The monkeypox virus is transmitted to people from various wild animals but has limited secondary spread through human-to-human transmission.
• Typically, case fatality in monkeypox outbreaks has been between 1% and 10%, with most deaths occurring in younger age groups.
• There is no treatment or vaccine available although prior smallpox vaccination was highly effective in preventing monkeypox as well.

---

Monkeypox is a rare viral zoonosis (a virus transmitted to humans from animals) with symptoms in humans similar to those seen in the past in smallpox patients, although less severe. Smallpox was eradicated in 1980.However, monkeypox still occurs sporadically in some parts of Africa.

Monkeypox is a member of the Orthopoxvirus genus in the family Poxviridae.

The virus was first identified in the State Serum Institute in Copenhagen, Denmark, in 1958 during an investigation into a pox-like disease among monkeys.

Outbreaks

Human monkeypox was first identified in humans in 1970 in the Democratic Republic of Congo (then known as Zaire) in a 9 year old boy in a region where smallpox had been eliminated in 1968. Since then, the majority of cases have been reported in rural, rainforest regions of the Congo Basin and western Africa, particularly in the Democratic Republic of Congo, where it is considered to be endemic. In 1996-97, a major outbreak occurred in the Democratic Republic of Congo.

In the spring of 2003, monkeypox cases were confirmed in the Midwest of the United States of America, marking the first reported occurrence of the disease outside of the African continent. Most of the patients had had close contact with pet prairie dogs.

In 2005, a monkeypox outbreak occurred in Unity, Sudan and sporadic cases have been reported from other parts of Africa. In 2009, an outreach campaign among refugees from the Democratic Republic of Congo into the Republic of Congo identified and confirmed two cases of monkeypox. Between August and October 2016, a monkeypox outbreak in the Central African Republic was contained with 26 cases and two deaths.

Transmission

Infection of index cases results from direct contact with the blood, bodily fluids, or cutaneous or mucosal lesions of infected animals. In Africa human infections have been documented through the handling of infected monkeys, Gambian giant rats and squirrels, with rodents being the major reservoir of the virus. Eating inadequately cooked meat of infected animals is a possible risk factor.

Secondary, or human-to-human, transmission can result from close contact with infected respiratory tract secretions, skin lesions of an infected person or objects recently contaminated by patient fluids or lesion materials. Transmission occurs primarily via droplet respiratory particles usually requiring prolonged face-to-face contact, which puts household members of active cases at greater risk of infection. Transmission can also occur by inoculation or via the placenta (congenital monkeypox). There is no evidence, to date, that person-to-person transmission alone can sustain monkeypox infections in the human population.

In recent animal studies of the prairie dog-human monkeypox model, two distinct clades of the virus were identified – the Congo Basin and the West African clades – with the former found to be more virulent.

Signs and symptoms

The incubation period (interval from infection to onset of symptoms) of monkeypox is usually from 6 to 16 days but can range from 5 to 21 days.

The infection can be divided into two periods:

• the invasion period (0-5 days) characterized by fever, intense headache, lymphadenopathy (swelling of the lymph node), back pain, myalgia (muscle ache) and an intense asthenia (lack of energy);
• the skin eruption period (within 1-3 days after appearance of fever) where the various stages of the rash appears, often beginning on the face and then spreading elsewhere on the body. The face (in 95% of cases), and palms of the hands and soles of the feet (75%) are most affected. Evolution of the rash from maculopapules (lesions with a flat bases) to vesicles (small fluid-filled blisters), pustules, followed by crusts occurs in approximately 10 days. Three weeks might be necessary before the complete disappearance of the crusts.

The number of the lesions varies from a few to several thousand, affecting oral mucous membranes (in 70% of cases), genitalia (30%), and conjunctivae (eyelid) (20%), as well as the cornea (eyeball).

Some patients develop severe lymphadenopathy (swollen lymph nodes) before the appearance of the rash, which is a distinctive feature of monkeypox compared to other similar diseases.

Monkeypox is usually a self-limited disease with the symptoms lasting from 14 to 21 days. Severe cases occur more commonly among children and are related to the extent of virus exposure, patient health status and severity of complications.

People living in or near the forested areas may have indirect or low-level exposure to infected animals, possibly leading to subclinical (asymptomatic) infection.

The case fatality has varied widely between epidemics but has been less than 10% in documented events, mostly among young children. In general, younger age-groups appear to be more susceptible to monkeypox.

Diagnosis

The differential diagnoses that must be considered include other rash illnesses, such as, smallpox, chickenpox, measles, bacterial skin infections, scabies, syphilis, and medication-associated allergies. Lymphadenopathy during the prodromal stage of illness can be a clinical feature to distinguish it from smallpox.

Monkeypox can only be diagnosed definitively in the laboratory where the virus can be identified by a number of different tests:

• enzyme-linked immunosorbent assay (ELISA)
• antigen detection tests
• polymerase chain reaction (PCR) assay
• virus isolation by cell culture

Treatment and vaccine

There are no specific treatments or vaccines available for monkeypox infection, but outbreaks can be controlled. Vaccination against smallpox has been proven to be 85% effective in preventing monkeypox in the past but the vaccine is no longer available to the general public after it was discontinued following global smallpox eradication. Nevertheless, prior smallpox vaccination will likely result in a milder disease course.

Natural host of monkeypox virus

In Africa, monkeypox infection has been found in many animal species: rope squirrels, tree squirrels, Gambian rats, striped mice, dormice and primates. Doubts persist on the natural history of the virus and further studies are needed to identify the exact reservoir of the monkeypox virus and how it is maintained in nature.

In the USA, the virus is thought to have been transmitted from African animals to a number of susceptible non-African species (like prairie dogs) with which they were co-housed.

Prevention

Preventing monkeypox expansion through restrictions on animal trade

Restricting or banning the movement of small African mammals and monkeys may be effective in slowing the expansion of the virus outside Africa.

Captive animals should not be inoculated against smallpox. Instead, potentially infected animals should be isolated from other animals and placed into immediate quarantine. Any animals that might have come into contact with an infected animal should be quarantined, handled with standard precautions and observed for monkeypox symptoms for 30 days.

Reducing the risk of infection in people

During human monkeypox outbreaks, close contact with other patients is the most significant risk factor for monkeypox virus infection. In the absence of specific treatment or vaccine, the only way to reduce infection in people is by raising awareness of the risk factors and educating people about the measures they can take to reduce exposure to the virus. Surveillance measures and rapid identification of new cases is critical for outbreak containment.

Public health educational messages should focus on the following risks:

• Reducing the risk of human-to-human transmission. Close physical contact with monkeypox infected people should be avoided. Gloves and protective equipment should be worn when taking care of ill people. Regular hand washing should be carried out after caring for or visiting sick people.
• Reducing the risk of animal-to-human transmission. Efforts to prevent transmission in endemic regions should focus on thoroughly cooking all animal products (blood, meat) before eating. Gloves and other appropriate protective clothing should be worn while handling sick animals or their infected tissues, and during slaughtering procedures.

Controlling infection in health-care settings

Health-care workers caring for patients with suspected or confirmed monkeypox virus infection, or handling specimens from them, should implement standard infection control precautions.

Healthcare workers and those treating or exposed to patients with monkeypox or their samples should consider being immunized against smallpox via their national health authorities. Older smallpox vaccines should not be administered to people with comprised immune systems.

Samples taken from people and animals with suspected monkeypox virus infection should be handled by trained staff working in suitably equipped laboratories.

WHO response

WHO supports Member States with surveillance, preparedness and outbreak response activities in affected countries.

 

 

EID Journal

Yinka-Ogunleye A, Aruna O, Ogoina D, Aworabhi N, Eteng W, Badaru S, et al. Reemergence of human monkeypox in Nigeria, 2017. Emerg Infect Dis. 2018 Jun [date cited]. https://doi.org/10.3201/eid2406.180017

Human monkeypox is a rare zoonotic infection caused by an orthopoxvirus and characterized by smallpox-like signs and symptoms (1). The disease is endemic to the Democratic Republic of the Congo. Reported outbreaks have occurred mainly in rural rainforest areas of the Congo basin and West Africa, caused by the Central and West African clades of the virus, respectively (1–6). The West African clade is associated with milder disease, fewer deaths, and limited human-to-human transmission. Since 1970, only ≈10 cases in West Africa had been reported; in 2003, a total of 81 cases (41% laboratory confirmed) were reported in the United States (2,7,8). In Nigeria, a case of human monkeypox in a 4-year-old child in the southeastern part of the country was reported in 1971 (4,5); no more cases in Nigeria had been reported since 1978 (2,6). We provide a preliminary report of a large outbreak of human monkeypox in Nigeria caused by the West African clade of monkeypox virus in 2017.

On September 22, 2017, the Nigeria Centre for Disease Control (NCDC) was notified of a suspected case of monkeypox; the patient had been admitted to the Niger Delta University Teaching Hospital, Bayelsa State, in the South South region of Nigeria. Outbreak investigations commenced immediately; isolation of the suspected case-patient, laboratory testing, and contact tracing were conducted.

The patient was an 11-year-old boy with an 11-day history of fever, generalized rash, headache, malaise, and sore throat. Physical examination revealed generalized well-circumscribed papulopustular rashes on the trunk, face, palms, and soles of the feet and subsequent umbilication, ulcerations, crusting, and scab formation. The patient had associated oral and nasal mucosal lesions and ulcers and accompanying generalized lymphadenopathy. Similar signs and symptoms, with varying degrees of severity, developed in 5 other family members living in the same household. The index case-patient and 2 of his siblings reported a history of having had contact with a neighbor’s monkey 1 month earlier, but it cannot be ascertained if the monkey was the source of their infection; the monkey had no known history of illness.

After identifying these cases as being suspected monkeypox, the NCDC immediately deployed epidemiologists to Bayelsa State to support detailed outbreak investigations. Health authorities in all states of the country were notified to establish enhanced surveillance based on a standardized case definition. As notification of suspected cases from other states increased, on October 9, 2017, the NCDC activated a national Emergency Operations Centre to coordinate the response to an unusual evolving outbreak. All relevant stakeholders (e.g., ministries of health, agriculture and animal health, and information) were mobilized for a robust response. The NCDC rapidly developed interim guidelines and protocols; disseminated them to all states; and implemented intensive surveillance, public sensitization, community mobilization, and case management accordingly across all states.

Laboratory diagnosis (by real-time PCR, IgM serology, and genomic sequencing) were initially undertaken at Institut Pasteur (Dakar, Senegal), Redeemer’s University Laboratory (Ede, Nigeria), and the US Centers for Disease Control and Prevention (Atlanta, GA, USA). Further diagnostics took place later at the NCDC National Reference Laboratory with technical support from the US Centers for Disease Control and Prevention.

On October 13, 2017, the NCDC received laboratory confirmation of a human monkeypox outbreak in Nigeria. As of November 17, 2017, a total of 146 suspected cases had been reported from 22 of the 36 states in Nigeria (Figure). Of the 134 samples (blood, lesion swab, and crust) collected during the reporting period, 107 samples were tested, and 42 samples from 14 states were laboratory confirmed as the West African clade of the monkeypox virus. Most (62%) of the laboratory-confirmed cases were in adults (21–40 years of age; median 30 years of age); the male:female ratio was 2:1. A 46-year-old male patient with confirmed monkeypox and a history of immunosuppressive illness died. For some patients with suspected (but ultimately deemed negative) cases of monkeypox, chickenpox (wild-type virus) was confirmed. Further analysis of the monkeypox-negative samples is ongoing.

Although detailed epidemiologic investigations to ascertain the source and route of transmission are ongoing, 3 family clusters were found, which might suggest some level of human-to-human transmission in this outbreak. For 1 of the families, the secondary attack rate was 71%. However, most patients had no obvious epidemiologic linkage or person-to-person contact, indicating a probable multiple-source outbreak or possibly previously unrecognized endemic disease. The zoonotic source(s) of the outbreak are currently unknown, and it is unclear what, if any, environmental or ecologic changes might have facilitated its sudden reemergence.

This large outbreak of West Africa clade human monkeypox (3,8,9) mostly affected adults. The NCDC continues response activities and investigations in collaboration with national and international partners. Further findings from our epidemiologic investigations and laboratory diagnostics, including genome sequencing, will add to the existing knowledge of West African monkeypox and help unravel uncertainties in the outbreak.

Outbreak News

CDC

Signs and Symptoms

 

MMWR

“……What is already known about this topic?

Human monkeypox is a viral zoonosis that occurs in West Africa and Central Africa. Most cases are reported from Democratic Republic of the Congo. The disease causes significant morbidity and mortality, and no specific treatment exists.

What is added by this report?

Nigeria is currently experiencing the largest documented outbreak of human monkeypox in West Africa. During the past decade, more human monkeypox cases have been reported in countries that have not reported disease in several decades. Since 2016, cases have been confirmed in Central African Republic (19 cases), Democratic Republic of the Congo (>1,000 reported per year), Liberia (two), Nigeria (>80), Republic of the Congo (88), and Sierra Leone (one). The reemergence of monkeypox is a global health security concern.

What are the implications for public health practice?

A recent meeting of experts and representatives from affected countries identified challenges and proposed actions to improve response actions and surveillance. The World Health Organization and CDC are developing updated guidance and regional trainings to improve capacity for laboratory-based surveillance, detection, and prevention of monkeypox, improved patient care, and outbreak response……”