BUBONIC and pneumonic plague occurred in the Rohru area in November 1966, killing eight people in Bhaunda and Larot villages. In 1957, cases of plague had been reported from some areas.
In 1966, the National Institute of Communicable Diseases (NICD) came up with detailed suggestions regarding plague surveillance. Pointing out that sylvatic reservoirs and their distribution were yet to be defined and delimited, experts warned against any complacency in dealing with plague.
The disease broke out once again in 1983, killing 17 persons in Rohru. The samples were sent to the NICD. It was identified as plague but the report was not made public.
Experience shows that the area is prone to outbreaks of plague. Though the health authorities are aware of this, the people by and large do not know that they run the risk of contracting the disease from the forests in the area. Hunting is a hobby for some sections in these villages.
According to a paper authored by P.N. Sehgal, A.K. Krishnaswamy and S. Pattanayak, all formerly officials with the NICD, there are three known endemic zones in the country - along the Himalayan foothills in northern India; in the hilly tracts of the Vindhyas in Madhya Pradesh, in central India; and in the mountain ranges of South India (the Deccan plateau) in Andhra Pradesh, Tamil Nadu (Chennai), Karnataka (Mysore) and Maharashtra. Sylvatic infection persisted in these regions, they have said in the paper which deals with the outbreak of plague in Himachal Pradesh in 1966. Other experts had also warned around the same time about the potential danger to the country from plague.
In 1967, six cases of plague were reported. The next reported incidence of plague was in Surat in 1994. The incidence of plague in Himachal Pradesh in 1983 went unreported.
Isolated pockets prone to plague exist all over the world, and India is no exception. Between 1954 and 1998, many countries, including Peru, Brazil, Madagascar, Vietnam, Uganda, the Democratic Republic of Congo, Tanzania, Mozambique, Myanmar, Ecuador, Bolivia and the United States, reported sporadic to relatively large number of cases of plague. But, evidently, mechanisms of surveillance are in place in these countries and the outbreak of the disease is restricted to isolated pockets.
Describing the plague outbreak of 1966, Sehgal and others noted, after epidemiological investigations, that the main signs and symptoms of the disease were high fever and enlargement of the auxiliary lymph glands. As none of the five cases in Larot village had been treated by any medical personnel, the details were collected from the neighbours and relatives of the deceased. All the five cases occurred in one family. Though the exact aetiology of the episode could not be determined, clinical diagnosis of three cases examined by medical officers from Himachal Pradesh and Sehgal concluded that it was indeed plague. Sehgal, a former Director of the NICD, is with the Voluntary Health Association of India (VHAI) as a consultant on public health and epidemiology.
Sehgal told Frontline that it was postulated that the plague in Larot village could have been caused by some wild rats that migrated from the surrounding forests after the first snowfall in November 1966. He said: "In the forest area, sylvatic foci are naturally existent in forest rodents. The rat flea bites the infected rat and then attaches itself to another rat. In 10 to 20 per cent of the cases, the infection becomes pneumonic. Man-to-man transmission occurs when a primary case of bubonic plague develops secondary pneumonic plague and infects contacts via the respiratory route."
In bubonic plague, Sehgal explained, the infected rat fleas usually bite on the lower extremities and the patient develops sudden fever, chills, headache and so on. Usually, within a few days, greatly enlarged buboes or tender lymph nodes develop in the groin and less often in the neck. When suppuration (pus formation) occurs, it is considered a sign of hope. Bubonic plague does not spread from person to person as the bacilli are locked in the buboes and do not find an easy exit. Human plague is invariably contracted from either the bite of an infected flea or occasionally by direct contact with the tissues of the infected animal or by droplet infection from cases of pneumonic plague.
The outbreak was restricted because of the isolated location of the houses in those villages. The disease spread to Bhaunda as people migrated from Larot. Measures taken by the local health authorities also helped contain the disease. The need to carry out investigation to determine the extent and presence of the foci of sylvatic plague in the area was stressed whenever there was an outbreak of plague. The lessons, it appears, have not been learnt.