<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META http-equiv=Content-Type content="text/html; charset=iso-8859-1">
<META content="MSHTML 6.00.2900.2523" name=GENERATOR>
<STYLE></STYLE>
</HEAD>
<BODY bgColor=#ffffff>
<DIV><FONT face=Arial size=2><FONT face="Times New Roman" size=3><FONT
face=Arial size=2>Parasites causing CL in Balochistan </FONT> <FONT
face=Arial size=2>have been typed as <EM>L. major</EM> and, from the landscape
epidemiology, the reservoir will be gerbils, the vector will be <EM>P.
papatasi</EM> (and perhaps the closely related species <EM>P. salehi</EM> in
Sindh) and the disease is Old World zoonotic cutaneous leishmaniasis (ZCL)
which, in most cases, will self cure in 6 months leaving the patient immune to a
further episode. (CL caused by <EM>L. tropica</EM>, which occurs in other parts
of Pakistan, is another story.) There has been a high prevalence clinically
recognisable ZCL recorded in this province every year for many years. Perhaps it
is exaggerating to say there is an outbreak at the moment, when nothing has
changed. Aerial spraying should not even be considered. It is not cost
effective, it cannot be maintained and it is probably disastrous for the
population dynamics of sand flies. Virtually nothing is known of the predators
of sand flies but there must be some that are doing a good job - or we'd be knee
deep in sand flies. Spraying will kill predators and, when spraying stops, it is
very unlikely they will recover as fast as the sand flies. The immune proportion
of the human population will have fallen, the population of vectors will have
risen, and a real epidemic can be expected. WHO recommended short term spraying
only when there is an epidemic of a life threatening form of leishmaniasis such
as kala-azar in the Indian subcontinent. With regard to house spraying, it
is not a fair comparison to assume that house spraying against <EM>P. papatasi
</EM>would be as effective as it appears to have been against <EM>P.
</EM>argentipes, the Indian vector of visceral leishmaniasis. The behaviour of
the <EM>P. papatasi</EM> is totally different from that of the Indian fly and I
know of no instance where house spraying against Old World ZCL has been shown to
be cost-effective. (Please correct me if I'm wrong.) The only real success story
I know of is the destruction of the habitat on the steppes of Central Asia
followed by planting rice, cotton or winter wheat to prevent reversion to
the original conditions (which later turned out to be an environmental
catastrophe for the Aral Sea). ZCL of the Old World, although a public health
problem, is not life-threatening and in some countries it is left to run its
natural course except with patients with multiple lesions or with lesions in
dangerous places such as the nose, eyelid etc. If that sounds unsympathetic and
cruel, all I can say is that's how Tony Bryceson 'treated' me when I had ZCL.
</FONT></FONT></FONT></DIV>
<DIV><FONT face=Arial><FONT size=2>Bob
Killick-Kendrick</FONT></DIV></FONT></BODY></HTML>