Published Date: 2011-01-15 19:00:04
Subject: PRO> Malaria - India (03): (Mumbai) comment
Archive Number: 20110115.0172
MALARIA - INDIA (03): (MUMBAI) COMMENT
A ProMED-mail post
ProMED-mail is a program of the
International Society for Infectious Diseases
Date: Thu 13 Jan 2011
From: Yuvaraj Jayaraman <email@example.com> [edited]
Malaria in Mumbai: comment
Malaria in cities need not only be endemic but can also be introduced by
migrants from endemic areas to cities in search of jobs. These migrants can
be low level of parasitemia [and asymptomatic].
When vector population is high, especially around construction sites,
mosquitoes easily pick up infection from these infected migrants. Since
sexual reproduction of these parasites occurs in mosquitoes, transmission
is rampant and on a wide scale.
One has to remember those cases that come to hospitals are the tip of the
iceberg, there might be many more cases treated elsewhere. What Mumbai
requires now is investigation of these outbreaks (from where the patients
come) to stamp out the local foci of transmission.
Unless this is taking place, cases of malaria will troop into hospitals.
Hence the physicians reporting cases here should also make an official
report to the Brihan Mumbai Corporation to enable them to initiate
Malaria may be usually low in December and January, but the climate now is
warmer facilitating the longer lifespan of mosquitoes and an increase in
number of cases. Also, with the above coupled with poor/inadequate control
measures, the situation will get out of control.
Yuvaraj Jayaraman MD (Pub Health)
National Inst of Epidemiology (ICMR)
[ProMED-mail thanks Dr Yuvaraj for his comment. We agree that malaria
transmission can be initiated by migrants being gametocyte carriers in
areas where there is a suitable _Anopheles_ vector and the climatic
conditions permits malaria transmission. However, the number of reports in
Mumbai clearly indicate that the point where a few local outbreaks could be
explained from breeding at construction and immigrant labor, has been passed.
It seems that local transmission from a human reservoir is now happening in
Mumbai. There is probably a reservoir of malaria in the poorer areas of
Mumbai. A survey of slum, squatter, and pavement dweller communities of
Mumbai City published in 2002, found that annual diarrhoea, typhoid, and
malaria cases were estimated to be 614, 68, and 126 per 1000 population
respectively (Kumar Karn S, Harada H: Field survey on water supply,
sanitation and associated health impacts in urban poor communities -- a
case from Mumbai City, India. Water Sci Technol. 2002; 46(11-12): 269-75;
If indeed there is a malaria incidence of 126 per 1000 population per year
in the poorer areas of Mumbai, it is clear that small changes in vector
distribution and density can easily explain the spread of malaria to more
affluent parts of the city. - Mod.EP]