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Fly problem in Cape Town
The South African Museum has had regular queries over the past 3 years
regarding an upsurge in the fly population in the Cape Peninsula and Cape Flats and most of the queries have
originated from the Bellville and Durbanville Health Departments. Specimens of the fly in question were sent to a fly
specialist in Pretoria and it has been repeatedly identified as the Sheep
blowfly Lucilia
cuprina (Diptera: Calliphoridae).
Calliphorid and sarcophagid
flies are attracted to exposed meat, carrion, human and animal excrement and any
rotting organic material and filth in general and they also readily infest open
wounds. The housefly Musca domestica also breeds
in rotting organic matter, but not usually meat and carrion. These flies are also attracted to human foodstuffs rendering them undesirable
in the home as they can carry organisms that threaten our health.
Toward the end of summer of 1998, the possibility of
dysentery breaking out was a concern and on 16 May 1999 a report in Sunday Time
Cape Metro confirmed this with subsequent reports, in the Cape Times on 15 July
1999 and in the City Late on 21 July 1999. Many cases were reported and there
were also some fatalities. Dysentry often results from gastroenteritis and if left
untreated, patients die due to dehydration and shock resulting from the loss of
body fluids.
Reasons for the sudden recent upsurge in the fly
population
It can only be surmised that the upsurge of this fly
population is directly related to three possibilities:
- the upsurge in informal settlements where there is
generally a poor state of sanitation;
- a change in the refuse collection system from black
bags to the trolley system. With the latter there is a lower collection
frequency (once a week) and the cleaning of the bins is inclined to be neglected creating
ideal breeding grounds for flies. In summer, these flies can pass
through a complete life cycle within a week so they have successfully bred
in the refuse by the time it has been collected.
- general filth such as dog faeces, left lying around
will aggravate the matter further.
There are also animal health issues in informal
settlements. On 3 December 1999, AM Live interviewed the head of
veterinary services of the Western Cape, Dr R.F. Visser, who explained how brucellosis (an infectious bacterial disease affecting cattle, sheep and goats
that causes undulant fever in man) is on the increase in cattle in the Western
Cape. Brucellosis is not transmitted by flies but this highlights another
potential problem. Our informal settlements all over the country keep livestock
of all descriptions and our municipalities are having difficulty in instituting
livestock and dairy health procedures in these areas. This could exacerbate the
problems caused by poor sanitary conditions.
Text by Margie Cochrane
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