Public health officials had warned of the likelihood of outbreak of infectious diseases in the aftermath of the Kerala floods, and the State is battling a disease called leptospirosis, commonly known as ‘rat fever.’ Officials have confirmed 143 cases, with six deaths in the first four days of September.
What is leptospirosis?
Leptospirosis is a zoonotic, or animal-borne, disease, caused by the bacteria of the genus Leptospira. It is largely found in animals, and occasionally surfaces in humans. It is most commonly spread through water contaminated by urine from infected animals, but contaminated food or soil can also act as vehicles for the disease. The key carriers are rodents, livestock and dogs, and that is why it is also known as ‘rat fever.’ Men — according to government guidelines — suffer more frequently from leptospirosis than women because of greater occupational exposure to infected animals and contaminated environment. Leptospiral infections occur more frequently in the 20-45 age group and it rarely happens in children. Much like dengue, it can manifest itself as no more than a mild flu and progress to a severe form that can cause kidney damage, liver failure, respiratory distress, meningitis, and even death. About 90% of leptospirosis cases manifest mild symptoms and the fatality rate can go as high as 15%, according to the Health Ministry. The authorities in Kerala have clinically confirmed 891 cases and 41 deaths this year.
Does it happen often?
Leptospirosis outbreaks have frequently been reported in Kerala since the 1980s and are linked to flooding. The last major episode of leptospirosis was during 2013 when Kerala received more rain than this year. Key regions that have historically reported notable incidence include Andaman and Nicobar, Gujarat, Maharashtra, Karnataka and Tamil Nadu. The frontline medicine employed to contain leptospirosis outbreaks is doxycycline and there’s a standard protocol in the Kerala Health Department to control disease incidence. In view of the floods, State authorities have directed all workers involved in relief operations — fishermen, police, fire and rescue personnel — to consume the medicine. In case of symptoms such as fever, body pain, pain in leg muscles, yellowish hue in the eyes, variation in the amount and colour of urine, the afflicted ought to contact the nearest government health centre.
Is it under-reported?
According to the Health Ministry’s National Centre for Disease Control, “rapid ecological changes have caused many new zoonotic diseases to emerge and resulted in epidemics. Leptospirosis is one among them.” The reclamation of wasteland, afforestation, irrigation and changes in cropping patterns and agricultural technology have been important factors. The World Health Organisation estimates the incidence of leptospirosis between 0.1–1 cases/100,000 population a year in temperate, non-endemic areas and between 10–100 cases/100,000 population a year in humid, tropical, endemic areas. However, India officially records no more than 10,000 cases annually. One of the key challenges is that it is a neglected disease with very little resources to investigate its extent. In a study in the peer-reviewed PLoS Neglected Tropical Diseases, a group of researchers reported that even north India, so far considered non-endemic, had many more cases than supposed. Though dated, the study found that the incidence increased from 11.4% in 2004 to 20.5% in 2008. Moreover, several of the cases so discovered presented themselves with complications such as renal failure, respiratory failure and neuroleptospirosis.
How seriously is it taken?
The Health Ministry has a protocol called the ‘Programme for Prevention and Control of Leptospirosis’ since 2015. Because leptospirosis manifested several symptoms similar to dengue, malaria and jaundice, it was frequently “overlooked” and therefore it has advised the States to use blood test and serology to identify cases. It also has a detailed procedure for lab technicians to take body fluids samples for testing.