After the disastrous flood, Kerala is now battling rat fever. So far 100 cases have been reported positive for rat fever. Rat fever, also known epidemic arthritic erythema, is spread by rodents. Rats are natural carriers of the causative bacteria but rarely show signs of illness. The majority of cases of fever is caused by rat bites or scratches.
In Asia, Spirillum minus is the major causative agent. Spirullum Rat Bite fever is famously called Sodoku fever. Rat fever is non-communicable. S.minus is produced only by the bite/scratch of a rat. Sometimes handling infected rats and exposure to their body secretions cause the disease. Rat alone cannot be blamed; other animals like weasels, gerbils, and squirrels or household pets such as dogs or cats exposed to these animals can also carry the disease and infect humans.
Following rat bite there is an incubation period of 1-4 weeks. Initially the wound exhibit slow healing with marked inflammation but suddenly exacerbation of the wound, with the local development of pain, swelling and bluish purplish discoloration occurs. A nodule or chancre-like ulcer may develop at the initial site. The lesions become purplish red, enlarge and form distinct plaques in the skin. The fever lasts longer and is intermittent type with 2-4 days cycle. Rise in body temperature is usually associated with fever.
Another notable symptom is the swollen lymph nodes in neck, groin and underarm. It begins with fever followed by rashes in hands and feet rashes may spread to other parts of the body. Rashes usually start after the wound begins to heal. Symptoms may differ also. Usually antibiotics are administrated for rat fever.
Initial diagnosis relies only on specific stains like Giemsa stain as this bacterium cannot be cultured on synthetic media. Blood smears or tissue from lesions or lymph nodes are usually taken. The WBC count ranges between 5,000 and 30,000/μL. The VDRL results are false-positive in half the patients.
To reduce the chances of rat fever is by obviously staying away from rodents. If a rat bites or scratches you, immediately wash the wound with soap and warm water, then cover the wound with dry dressing and immediately consult a doctor. Antiseptics may be applied. Remove the jewels and ornaments around the wound as there may be swelling. The disease may easily be confused with malaria or Borrelia recurrentis infection as both are characterized by relapsing fever.
Only pasterurized milk and water from safe sources should be ingested. Unpasterurized milk is unsafe and had also lead to an outbreak in Haverhills in1926. Also, it is interesting to note that rats are not a major source of rabies infection – a common misconception. Rabies transmission from rodents to humans is extremely rare, so at least you don’t have to worry about that.
With proper treatment the prognosis is positive. But if left untreated, it leads to complications include myocarditis, endocarditis, hepatitis, splenomegaly, and meningitis. It can lead to infection in heart, brain and lungs. It may also cause abscess in internal organ. It is associated with a mortality rate of 13% in untreated cases.
What precautions are to be taken? Regarding Kerala people are mostly affected while cleansing their homes. Wild rodents, dead or alive, should not be touched. Make sure you wear gloves while cleaning your home. Regular hand washing, and avoiding hand-to-mouth contact when handling rats or cleaning rat infested area is to be followed. Keep children away as children can easily get infected. Do not allow your pet dog or cats to ingest the rodents as they may also spread the disease to us.
Before cleaning, trap the rodents and seal the entryway of rodents. Set the trap till no rodents are captured. This ensures that the active infestation in the area has been abolished. Ventilate the space for at least 30 min- 1hr.use cross ventilation and ensure everyone is away before the airing out starts. When you do the clean-up ensure that you don’t mix up dust with rat urine and droppings. This may lead to infection of people who come in contact with the dust. Wear rubber or latex gloves. Spray the urine or droppings with disinfectant or bleach with water. Leave it for 5-10 min. Using paper towel pick up the dropping and safely dispose it of in waste. Then clean the area with disinfectant.
Mop the floor twice or thrice with disinfectant. Stem cleanse or shampoo wash the furniture and carpets, regarding bedding and clothing wash it with detergents in hot water.
Ensure you wash your hands with soap and warm water after removing the gloves. Please make sure your home is fortified with rats.