VIRAL HAEMORRHAGIC DISEASES (LASSA FEVER AND EBOLA )

0
280

Viral Haemorrhagic Disease is a group of infectious diseases that aside from other symptoms also damage the blood vessels wall and/or interfere with the blood clotting ability, thereby causing severe illness sometimes associated with bleeding. Examples of Viral Haemorrhagic Disease are Lassa Fever, Ebola Virus Disease, Yellow Fever, Dengue Fever, Crimean-cargo Haemorrhagic Fever, etc.

Viral Haemorrhagic Diseases are caused by contact with infected animals and insects (rodents, monkeys, bats, mosquitoes, ticks, etc). Man to man transmission does also occur in the spread of Viral Haemorrhagic Disease. Generally, symptoms include high fever, fatigue, dizziness, weakness, muscle aches, joint pain and sometimes bleeding.

Risk factors for the transmission of the infections include; contact with the sick, slaughtering and preparation of infected animals, sharing of needles, intravenous drug use, having unprotected sex, working or living in vector infested areas, exposure to infected blood and body fluids, etc. Complications of Viral Haemorrhagic Disease are brain damage, heart failure, kidney failure, liver failure, respiratory problems, etc.

Prevention is generally by avoiding risk factors, use of personal protective devices in handling animals / infected materials and vaccination if available. Treatment is mostly by supportive management, symptom management, and close monitoring.

Lassa Haemorrhagic Fever (LHF)

Lassa Haemorrhagic Fever is one of the Viral Haemorrhagic Diseases. It is caused by the Lassa virus; a single-stranded RNA virus belonging to the family Arenaviridae.

Lassa fever is a zoonotic disease arising in humans as a result of contact with infected animals. The animal reservoir or host of the Lassa virus is a rodent of the genus Mastomys; commonly called Mastomys rat. The rat is a multimammate rat (multiple nipple rat) which when infected with the virus do not become ill but can shed the virus in urine and faeces. When human have contact with the urine and faeces of lassa infected Mastomys rat, he or she contacts Lassa infection which can progress to Lassa fever in about 20% of cases. In others, the infection can fail to progress with no clinical symptoms.

Lassa fever was first reported in Borno State of Nigeria in a town called Lassa when two Missionary Nurses died from an unusual febrile illness. The disease is however endemic in West African countries such as Benin, Ghana, Guinea, Liberia, Mali, Sierra Leone, and Nigeria. In 2018, the largest ever a number of cases was reported in Nigeria by NCDC with over 600confirmed cases and 170 deaths.

In the transmission of Lassa fever, human usually becomes infected with the virus as a result of exposure to urine or faeces of infected Mastomys rat. The urine or faeces can contaminate food, utensils, etc. An infected human can also transmit it to another human through direct contact with blood, urine, faeces and other body fluids and secretion.  This can occur in the community as well as in hospital settings.

Lassa fever can occur in all age groups and in both sexes. Risk of infection increases with habitation in areas where Mastomys rat are usually found such as rural areas, bushy areas, communities with poor sanitation, crowded areas, etc.

Symptoms of Lassa fever occurs after between 6-21days (incubation period) of infection with the virus. Symptoms include fever, generalized body weakness, malaise, headache, sore throat, muscle pain, chest pain, nausea, diarrhea, cough, and abdominal pain. In severe cases, facial swelling, difficulty in breathing, bleeding from the mouth, nose, vagina and gastrointestinal tract can occur. Also, low blood pressure may develop. Some patients can progress to seizure, tremor, disorientation, shock, coma, and death can occur.

80% of those infected might not develop the disease and will show no clinical symptom, but the remaining 20% can progress to clinical disease with varying outcomes. The overall case fatality rate of Lassa fever is 1%, while the case fatality rate among hospitalized patients can be as high as 15%. Death usually occurs within 14days of onset in fatal cases. Deafness can occur in 25% of survivors with half of this percentage recovering their hearing after some time. Also, the disease can be severe in pregnant women especially when in the last three months of pregnancy.

Diagnosis is by clinical symptoms with a high index of suspicion and laboratory test in specialized reference laboratories.

Treatment is usually with the use of an antiviral drug called ribavirin under doctors’ prescriptions. The treatment is more effective when introduced early in the course of clinical illness. Supportive treatment is very important.

Prevention and control of Lassa fever is hinge on activities that will prevent the presence or contact with the vector (Mastomys rat). These include:

  • Health Education and awareness campaign about the disease especially during the dry season when rats leave the bush to reside around the houses.
  • Community hygiene
  • Household hygiene
  • Storing foods in rodent-proof containers to avoid rat contact
  • Thorough washing of eating and cooking materials before use
  • Garbage and wastes should be disposed of far away from homes
  • Methods to catch or kill Mastomys rats
  • Avoid contact with multi-mammate rats
  • Special self-care while caring for sick persons

Ebola Viral Disease (EVD)

Ebola Viral Disease is a rare but often fatal acute illness caused by the Ebola virus. It first appeared in 1976 in two simultaneous outbreaks; one in Nzara, South Sudan and the other in Yamkubu, Democratic Republic of Congo (DRC). The name Ebola was derived from the occurrence in Yamkubu; a village near Ebola River in the Democratic Republic of Congo (DRC).

The largest outbreak was in 2014-2016 in which the disease outbreak enraged some West African Countries; vis a vis Guinea, then Sierra Leone, Liberia. The recent outbreak of 2018-2019 was in the Eastern Democratic Republic of Congo (DRC) with high complexity and adverse public health effect.

Transmission of the Ebola Virus Disease is by close contact with blood, secretions, organs or other body fluids of infected animals such as fruit bats, chimpanzees, gorillas, monkeys, forest antelopes or porcupines. Human to human transmission can also occur by direct contact (broken skin or mucous membrane) with blood and other body fluid of the sick or dead body of Ebola victim. Also, objects contaminated with secretions, blood, vomiting, faeces etc of Ebola patient can spread the disease.

It is worthy of note that Ebola patients or victims remain infectious alive or dead and as long as the virus remains in their blood.

Symptoms of Ebola Viral Disease appear between 2-21days of infection. But infected persons cannot spread the disease until symptoms develop. These symptoms are fever, fatigue, muscle pain, headache, and sore throat. Others include vomiting, diarrhea, rash, impaired kidney function, impaired liver function, internal or external bleeding from the gum, stool etc.

Diagnosis is based on a high index of suspicion from clinical symptoms and confirmation of laboratory results from a specialized reference laboratory.

Ebola Viral Disease is a very fatal disease with an average fatality rate of around 50% (ranges between 25-90%)

Treatment is mostly supportive as there is no proven treatment available yet. Prevention is, therefore, the key to the war against Ebola.

Preventive strategies include:

  • Awareness campaign and health education of the population
  • Regular hand washing
  • Reduce human contact during outbreaks
  • Avoid unprotected contact with fruit bats, monkeys, apes, forest antelopes, porcupines and also reduce or prevent the consumption of their raw meat.
  • Animals should be handled with gloves and other appropriate protective clothing
  • Thorough cooking of meats before consumption
  • Avoid contact with sick patients except with protective clothing.
  • Safe burial practices of all deaths
  • Abstinence from sex if Ebola is suspected in partner
  • Vaccination with rVSV-ZEBOV vaccine during outbreaks

May Allah protect all us from these deadly infections and all others.

References

  1. Viral Haemorrhagic Diseases. Available at www.who.int>vhf. (Accessed on December 2019).
  2. Viral Haemorrhagic Diseases. Available at www.cdc.gov>vhf. (Accessed on December 2019).
  3. Lucas AO, Gilles HM. Short Textbook of Public Health Medicine for the Tropics, Revised Fourth Edition.
  4. Fact sheet on Viral Haemorrhagic Diseases. Available at www.ncdc.gov>factsheet. (Accessed on December 2019).