KOLKATA: Bacterial infection

, which is caused by a mite believed to be restricted to rural areas, may be on the verge of turning

. At least three private hospitals have reported half-a-dozen cases over the last month, where patients have been infected in the city. It has led doctors and experts to conclude that the chigger mite, which transmits the disease, has either migrated to Kolkata with the working population that travels from the suburbs or have been multiplying in conducive conditions within the city.

CMRI Hospital has made it mandatory to conduct an Elisa test on all

patients to detect scrub typhus. It led to the detection of the bacteria in two city patients, including one from Ballygunge, who had not travelled to rural areas. “This indicates that they were locally infected, which means the chigger is now present in the city,” said Debkishore Gupta, CMRI’s head of infection control and microbiology. “Even though the majority of scrub typhus patients are still from rural areas, the number of locally infected patients has risen significantly this year. This is alarming in a situation where dengue has already been claiming lives.” He added that since fever patients are rarely tested for the ailment, many scrub typhus cases could actually be going undiagnosed. Even though bite marks are visible in typhus patients, they remain untraceable in 40% cases.

Earlier this month, a patient from Tollygunge with fever and headache sought treatment at the RN Tagore International Institute of Cardiac Sciences (RTIICS). A test revealed scrub typhus even though he had not left the city in several months.

Shrubs, bushes and ill-maintained parks filled with weeds could be breeding the Leptotrombidium, also known as chigger, felt RTIICS consultant Arindam Biswas. RTIICS has received around 20 scrub typhus patients over the last six weeks, several of whom are suspected to have been infected locally.

Chigger mites breed in damp areas where vegetation is thick. “Conditions conducive to the breeding of chiggers exist in Kolkata. That apart, a large number of people travel to the city from the rural areas every day and could well be carrying the insect inadvertently. Vehicles plying into the city could be transporting it as well,” said Biswas. “Those engaging in gardening are at risk, for the chigger thrives in grasses and undergrowth,” Gupta warned.

Fortis Hospital has received several city patients over the last six weeks who were infected locally, though none was admitted in the last two months. “It’s possible the chigger has adapted itself to urban conditions. So, it could now be risky to assume that scrub typhus can strike only in rural areas,” said Fortis consultant Joydeep Ghosh.

Symptoms of the ailment include high fever, muscle pain, cough, gastrointestinal symptoms, liver and spleen enlargement and

in extreme cases.

can help control the disease in two days, Gupta said. “Initial symptoms are identical to any viral infection, so it can be deceptive. In case it’s not identified and antibiotics are not used, patients tend to deteriorate fast and may get meningitis or lapse into a coma. Sepsis is also common,” he warned.

In case fever persists for five days, Gupta recommends a test to rule out typhus. “We have been receiving one or two patients every week, who might have been infected locally,” he said. Doxycyclin is the best antibiotic and it can work in 24-48 hours, he added. Azythromycin is the recommended drug for pregnant women.

Usually, the mortality rate in scrub is 2%. It’s rarely fatal unless detected late. But since it has been occurring alongside dengue this year, delay in detection is likely due to overlapping symptoms. “We have decided to get every fever patient tested for scrub typhus,” said a

official.

“Scrub typhus is an important cause of acute febrile illness in India,” said Pritam Roy, a public health specialist. The World Health Organization (WHO) says that scrub typhus is probably one of the most underdiagnosed and under-reported febrile illnesses requiring hospitalization,” said Roy, the WHO coordinator for non-transmissible diseases in Bengal.