Ebola, Lassa Fever, off springs of the viral Haemorrhagic Family

What is Haemorrhagic Fever?
Carriers of viruses responsible for VHF
Facts you should know
Prevention and Control et al

Relationship between Lassa fever and the dreaded Ebola may have been established and there is a wide list of fevers in this chain classified as Haemorrhagic fevers
Haemorrhagic fevers includes the infamous Ebola, Lassa fever, Marburg haemorrhagic fevers, Crimean–Congo haemorrhagic fever (CCHF), Rift Valley fever (RVF), Hantavirus diseases, dengue and yellow fever
What is Haemorrhagic Fever?
Viral hemorrhagic fever is a viral infection and it refers to a group of illnesses that are caused by several distinct families of viruses
The term viral hemorrhagic fever” describes a severe multisystem syndrome because it may affect multiple organ systems in the body, Damage may be done to the overall vascular system and consequently impairs the body’s ability to regulate itself.
Hemorrhage is characterized by bleeding that is rarely life threatening. Whilst most of the hemorrhagic fever viruses cause severe life-threatening diseases, others can cause relatively mild illnesses.

The viruses that cause viral hemorrhagic fever (VHFs) belong to a unique family of four viruses known as flaviviruses, arenaviruses, bunyaviruses, and filoviruses.

Facts you should know:
  • All of these viruses require a reservoir such as animal or insect host. The reservoir can carry the virus but is not affected by the virus.
  • The viruses are geographically limited to the areas where their host species live.
  • Natural reservoir for any of these viruses does not include humans.
  • Humans can be infected by contact with infected hosts.
  • Humans can transmit the virus to one another following an accidental transmission from a host in some forms of the virus.
·         In few cases such as scrub typhus, some other viral and bacterial infections can cause hemorrhagic fever.
  • Outbreaks of hemorrhagic fevers occurring because of these viruses can be sporadic and irregular.
  •  Outbreaks are not easily predictable.
  • There is presently no cure or established drug treatment for most VHFs except for a few.
  • The family members are all RNA viruses, and all are covered, or enveloped, in a fatty (lipid) coating.
Carriers of viruses responsible for VHF
They are rodents, arthropods and some unknown host, for instance, the host of some viruses such as Ebola and Marburg viruses are unknown.
  • Rodents are the multimammate rat, cotton rat, deer mouse, house mouse including other field rodents.
  •  Arthropod: ticks and mosquitoes are vectors for some of the illnesses.

These viruses naturally reside in animals, hence they are referred to as zoonotic they reside in an animal reservoir host or arthropod vector.
They replicate via the host
They depend on the hosts for survival.

Transmission of the viruses causing hemorrhagic fever is by contact between humans and infected rodents or arthropod considered to be reservoir hosts or vectors of the virus. 
  • It can occur via contact with the waste or fluids of reservoir hosts or vectors. Waste such as urine, fecal matter, saliva, or other body excretions from infected rodents.
  • Arthropod vectors such as tick or mosquito spread the virus when they bite human, or when a human crushes a tick. Humans can also be infected when they provide care or slaughter their animals. This can occur because some of these vectors may also spread the virus to other animals, livestock. Secondary transmission can occur from person to person.

Signs and symptoms
Signs and symptoms may vary with the type of VHF, some of the initial signs and symptoms are
  • Fever, fatigue, dizziness, muscle aches, loss of strength, and exhaustion.
  • Bleeding under the skin, in internal organs, or from body orifices like the mouth, eyes, or ears may occur in severe cases..
  • Severe cases may include shock, seizures, nervous system malfunction, coma, delirium, renal kidney failure.

Beyond the anti-viral drug, “Ribavirin”, which has proven to be an effective solution to some persons with HFRS or Lassa fever and the Argentine hemorrhagic fever which is treated with convalescent-phase plasma treatment in some patients, there is no well known established cure for VHFs.

 Prevention and Control
In the absence of vaccine for most of these diseases, prevention and control measures must be focused on avoiding contact with the host species. Like the healthcare team in Lagos state, Nigeria, they are presently cleaning up the environment and installing rodent killer in several Local government councils across the state.

In case of VHF outbreaks, transmission from person to person can be prevented. Hemorrhagic fever viruses are mostly transmitted via rodents and can be prevented by
  • Rodent population control
  • Maintenance of clean environment
  • Take measures to prevent rodents from entering your house or office.
  • Ensure safe cleanup of rodent waste, nests et al .
In cases of hemorrhagic fever caused by viruses spread via arthropod vectors,
Community-wide insect and arthropod control can be used as prevention, measures include
  • The use of insect repellant
  • window screens
  • Bed nets,
  • Adequate clothing should be used and other insect barriers to avoid being bitten.

In cases of hemorrhagic fever viruses that can be transmitted between persons, the following measures can be taken;
  • Avoid close physical contact with infected persons
  • Avoid contact with their body fluids

Apply barrier nursing or infection control techniques such as
  • Isolation of infected persons
  • Use of disinfectants,
  • Proper disposal of instruments and equipment used for treatment of patients with VHF
  • Use of protective clothing

The excerpt below is from the U.S centre for disease control (CDC ) in conjunction with the World Health Organization,

They have both “developed practical, hospital-based guidelines, titled Infection Control for Viral Haemorrhagic Fevers In the African Health Care Setting.
The manual can help health-care facilities recognize cases and prevent further hospital-based disease transmission using locally available materials and few financial resources.

What should be done to curb VHF threats?

According to CDC, scientists and researchers are challenged with a three tier agenda
1.      “Develop containment, treatment, and vaccine strategies for these diseases.
2.      Develop immunologic and molecular tools for more rapid disease diagnosis, and to study how the viruses are transmitted and exactly how the disease affects the body (pathogenesis).
3.      Understand the ecology of these viruses and their hosts in order to offer preventive public health advice for avoiding infection”.

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