Issue #25   •   Quarter 3/4 Edition   •   December 2018

 

By Eyza Icha

It’s a sad testimony that Nigerians are now used to periodic disease epidemics, some deadly, some not so much. We are just coming out of the tail spin of Lassa fever in the country and now the latest scare is over the reported outbreak of Monkey Pox.

What started as a lone case of suspected Monkey pox disease in Bayelsa State spread within a few weeks to Ekiti, Akwa Ibom, Lagos, Ogun, Rivers and Cross River, Nassarawa, Enugu and recently the FCT. This is a tongue in cheek statement because the Minister for Health Prof. Isaac Adewole has stated previously that the news of the spread was mere conjecture and yet to be proved with laboratory test results.

What is Monkey Pox and what effect can it have on our individual daily lives? 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.

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.

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:

  1. 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);
  2. 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.

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.

References

The Guardian
Daily Trust
World Health Organization