A death due to Lassa fever in the UK has had some speculating whether India should be concerned about the emergence of yet another zoonotic condition.
Electron microscope view of the Lassa virus
The death occurred in a newborn baby in the town of Luton in the UK. The event came as a shock following three other cases as the disease is typically isolated to a few regions of Africa. The disease has not been reported in the UK for thirteen years. Guinea, Liberia, Sierra Leone, Nigeria, Benin, Ghana, and Mali are among the countries in West Africa where Lassa fever is currently endemic.
In India, the prevalence of the disease is as of yet unknown. International travellers have been reported with the condition upon returning to India. Given the potential for human-to-human transmission, it is possible that the disease has spread further after the travellers returned to India, however, there is no data on this matter.
The disease is typically spread by the rodent known as the “multimammate rat” (Mastomys natalensis). The rat is not native to India, and so, the chance of infection is limited to human contact with returning travellers. Once a rodent is infected by the virus, it excretes the virus in its urine for a prolonged period of time, potentially even for the rest of its life. Given the rapid breeding cycle of the rodent and large litter sizes, it is possible for an area to become ridden with infected rodents in a short period of time.
“Lassa fever is accompanied with a wide range of clinical symptoms and its incubation period is between one to three weeks. Prior to the start of symptoms, Lassa fever patients are not thought to be contagious. The majority of infected people experience moderate symptoms (about eighty percent), such as a low-grade fever, lethargy, and headache, and may not seek medical care,” says Dr. Manish Wadhwani, consultant intensivist at Masina Hospital.
Zoonotic conditions are an ever present threat in India. With so many of the population living in rural locations, many of which work directly with livestock animals, zoonotic diseases are both varied, and common. As Health Issues India previously noted, quoting a study on the matter, “zoonotic diseases have been increasing globally as well as in India. Of 1407 human pathogens, 816 were zoonotic…These include 538 bacteria and rickettsia, 317 fungi, 208 viruses, 287 helminths, and 57 protozoa. The study also highlighted that as many as 177 (thirteen percent) of the total pathogens were emerging or reemerging, and of these 130 (75 percent) were classified as zoonoses.”
Lassa fever is a treatable disease, and without the host animal species being present in India, chance of transmission is low. However, the fact that a newborn has died in the UK from a disease endemic to Africa illustrates the fact that zoonoses can emerge unexpectedly, underlining the importance of screening.
