Rabies

Rabies virus; General overview, signs and syptoms, prevention and treatment

Rabies

Rabies

Rabies is a viral disease that affects the central nervous system (CNS). There are 10 viruses in the rabies serogroup, most of which only rarely cause human disease.

We have two forms of rabies which include furious form and paralytic form of rabies.

Rabies infection is caused by the rabies virus. The virus is spread through the saliva of infected animals.

The animals most likely to transmit the rabies virus to people include; cats, cows, dogs, goats, as well as bats, foxes, monkeys, raccoons, and shakunks.

INCIDENCE

Rabies is more prevalent in the developing world than in industrialized countries.

In Africa, the reservoirs are mainly; dogs, mongoose, and antelopes. Encounters with rabid animal vectors may be increased in males, who may have greater contact in certain geographic areas. Data on dog bites revealed much higher in males than females.

PATHOPHYSIOLOGY

There is an introduction of the virus through a bite

. Movement of the runs into the brain slowly

Incubation period. The time it takes the virus to move from the site of the bite to the brain. Ranges from 2 weeks to several months.

Prodromal stage. where the patient will exhibit signs of malaise, anorexia, headaches, fever, chills, pharyngitis, anxiety, insomnia and depression. Duration is about 2-10 days

Acute neurologic phase. The hAs duration period of 2-7 days, symptoms include outmuscling fasciculationpriapism, and focal or general convulsions. Patients may die immediately or progress to paralysis, which may be present only in a bitten limb at first but usually becomes diffused.

The patient can be in coma after this period and if intensive supportive care is not available, depression, arrest, and death can occur shortly after coma.

Signs and symptoms

No clinical signs are characteristic of rabies and differential diagnosis may involve many agents or syndromes. Initial symptoms often include;

  • Fever
  • Pain
  • Unusual tingling
  • Pricking or burning sensation (paraesthesia)
  • Muscle spasms
  • Paralysis
  • Mental confusion
  • Furious rabies accounts for approximately 80% of the total number of human cases; manifesting as signs of hyperactivity, hypersalivation, and periods of agitation altering with lucidity, hydrophobia and sometimes aerophobia. After a few days, the infection invariably leads to coma and death by cardiorespiratory attack
  • Paralytic (or dumb) rabies accounts for approximately 30% of the total number of human cases. This form of rabies runs a less dramatic but longer course than the furious form. There is flaccid muscle weakness in the early onset of infection, starting at the site of the bite, followed by gradual paralysis. Death by respiratory failure is generally preceded by the development of ca oma. The paralytic form is often misdiagnosed, contributing to the underreporting of the disease

DIAGNOSTIC MEASURES

  • Tests are performed on samples of saliva, serum, spinal fluid, and skin biopsies of hair follicles at the nape of the neck.
  • Saliva can be tested by virus isolation or reverse transcription followed by polymerase chain reaction (RT-PCR).
  • Serum and spinal fluid are tested for antibodies to the rabies virus. Skin biopsy specimens are examined for rabies antigen in the cutaneous nerves at the base of hair follicles.
  • A special test called immunofluorescence is used to look at the brain tissue after an animal is dead. This test can reveal whether or not the animal had rabies.

MEDICAL MANAGEMENT

All cases of suspected exposure to rabies should be treated immediately in order to prevent the onset of symptoms and death. post-exposure prophylaxis consists of local treatment of the wound, a course of potent, effective rabies vaccine that meets WHO recommendations and administration of rabies immunoglobulin (if indicated).

Rabies shots include:

  • A fast-acting shot (rabies immune globulin) to prevent the virus from infecting you. Part of this injection is given near the area where the animal bit you if possible, as soon as possible after the bite.

A series of rabies vaccines to help your body learn to identify and fight the rabies virus. Rabies vaccines are given as injections in your arm. You receive four injections over 14 days.

PREVENTION

  • Eliminating rabies in dogs: Rabies is a vaccine-preventable disease. Vaccinating dogs is the most cost-effective strategy for preventing rabies in people. Dog vaccination will drive down not only the deaths attributable to rabies but also the need for PEP as a part of da dog bite patient care.
  • WHO promotes wider access to appropriate post-exposure treatment using the cost-effective multi-site intradermal regimen with modern tissue culture or avian embryo-derived rabies vaccines
  • Possible domestic production of rabies biologicals, particularly rabies immunoglobulin, which are in crcriticallyhort supply globally
  • Continual education of health and veterinary professionals in rabies prevention and control.
  • Public health educational strategies at the community level within the demic regimen

Other ways to prevent rabies include:

  • Consider the rabies vaccine if you’re traveling. If you’re traveling to a country where rabies is common and you’ll be there for a long period of time, ask your doctor whether you should receive the rabies vaccine.
  • Keep your pets confined. Keep your pets inside and supervise them when outside. This will help keep your pets from coming in contact with wild animals

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