Something on Scrub Typhus
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Dr L Bina Chanu
Scrub typhus is a feverlike disease caused by a bacterium that spread to human beings through the bite of a tiny, infected larval form of a bug known as chigger mite which is one of the larval stages of the mite. The mite is especially prevalent in rural, forested and bushy areas across many parts of Asian – Pacific regions. The disease is non-contagious meaning the disease is not transmitted from infected person to another non-infected healthy person.
In Manipur, scrup typhus is locally known as Khullai-laipha. 96% of most of the disease cases are reported from rural areas among the farmers who work in open fields and bushy terrains. The risk of the disease in Manipur is both across the valley and hilly terrains. In the districts like Kangpokpi and surrounding hilly forests having dense vegetation provides a perfect habitat for the chiggers and wild rodents.
In the history of Mani-pur, major outbreak of the particular disease has been recorded from Bishnupur district. The victims frequently suffered from cluster of fever with dark bite scabs known as eschars. All cases are associated with the rural environment where home borders are with secondary forest growths, bamboo groves and unwatched bushes.
The emergence of Khullai- laipha is seasonal and highly dependent on the local climate. The vectors which transmit the disease causing bacterium, require moisture, specific temperatures and shady areas to lay eggs and for breeding.
The massive surge of the diseases as recorded from the cases of Manipur are during July – November with the highest OPD and bed cases in the RIMS and JNIMS during the months of August, September and October.
With the arrival of monsoon rains, relative humidity also increases. With these, grass and wild shrubs grow rapidly creating ideal damp environments for the mites to multiply. As the heavy rains retreat, the cooler yet highly humid autumn Weather with a temperature of 15 degree and 28 degree permit the chiggers to remain highly active on the tips of long grasses, waiting to climb onto passing hosts.
Infection is contracted outdoors during agricultural practices. Farmers are the most vulnerable group marking up to nearly 60% of all recorded cases in the State. While working in the paddy fields and clearing wild weeds make them into direct contact with the chiggers that are inhabiting in those weed plants. The jhum cultivars while working on the forested hilly slopes face high exposure when clearing the dense underground. Grass cutters and wood collectors who routinely enter the bush to cut animal fodders and collecting firewood are at exceptional risk. Studies in Manipur have revealed unique risk factors, such as individuals who defecate or urinate in nearby jungles or bushy areas from a squatting position. This leaves low-hanging warm skin highly exposed to ground mites, frequently resulting in bite scabs (eschars) in the groin or perineal area. Homemakers also face risk if their daily chores involve fetching water or tending to outdoor gardens near heavy shrubbery.
The vector of scrub typhus is the trombiculid mite, specifically species belonging to the genus Leptotrombidium. While the adults are harmless, the disease is transmitted exclusively by the microscopic, parasitic larval stage of these mites, universally known as chiggers.
(To be contd)
Scrub typhus is a feverlike disease caused by a bacterium that spread to human beings through the bite of a tiny, infected larval form of a bug known as chigger mite which is one of the larval stages of the mite. The mite is especially prevalent in rural, forested and bushy areas across many parts of Asian – Pacific regions. The disease is non-contagious meaning the disease is not transmitted from infected person to another non-infected healthy person.
In Manipur, scrup typhus is locally known as Khullai-laipha. 96% of most of the disease cases are reported from rural areas among the farmers who work in open fields and bushy terrains. The risk of the disease in Manipur is both across the valley and hilly terrains. In the districts like Kangpokpi and surrounding hilly forests having dense vegetation provides a perfect habitat for the chiggers and wild rodents.
In the history of Mani-pur, major outbreak of the particular disease has been recorded from Bishnupur district. The victims frequently suffered from cluster of fever with dark bite scabs known as eschars. All cases are associated with the rural environment where home borders are with secondary forest growths, bamboo groves and unwatched bushes.
The emergence of Khullai- laipha is seasonal and highly dependent on the local climate. The vectors which transmit the disease causing bacterium, require moisture, specific temperatures and shady areas to lay eggs and for breeding.
The massive surge of the diseases as recorded from the cases of Manipur are during July – November with the highest OPD and bed cases in the RIMS and JNIMS during the months of August, September and October.
With the arrival of monsoon rains, relative humidity also increases. With these, grass and wild shrubs grow rapidly creating ideal damp environments for the mites to multiply. As the heavy rains retreat, the cooler yet highly humid autumn Weather with a temperature of 15 degree and 28 degree permit the chiggers to remain highly active on the tips of long grasses, waiting to climb onto passing hosts.
Infection is contracted outdoors during agricultural practices. Farmers are the most vulnerable group marking up to nearly 60% of all recorded cases in the State. While working in the paddy fields and clearing wild weeds make them into direct contact with the chiggers that are inhabiting in those weed plants. The jhum cultivars while working on the forested hilly slopes face high exposure when clearing the dense underground. Grass cutters and wood collectors who routinely enter the bush to cut animal fodders and collecting firewood are at exceptional risk. Studies in Manipur have revealed unique risk factors, such as individuals who defecate or urinate in nearby jungles or bushy areas from a squatting position. This leaves low-hanging warm skin highly exposed to ground mites, frequently resulting in bite scabs (eschars) in the groin or perineal area. Homemakers also face risk if their daily chores involve fetching water or tending to outdoor gardens near heavy shrubbery.
The vector of scrub typhus is the trombiculid mite, specifically species belonging to the genus Leptotrombidium. While the adults are harmless, the disease is transmitted exclusively by the microscopic, parasitic larval stage of these mites, universally known as chiggers.
(To be contd)