They come in all sizes and are part of our lives. We meet them almost every hour, without appointment. They are flies. Every morning, thousands of people walk to a nearby restaurant, street vendor, spaza shop, or food outlet to buy a meal for breakfast – and flies will be there.
With food served in open spaces in Gaborone, it is common to see both the customer and the vendor fending off these irritating creatures that have a tendency of gate-crashing any place where there is a meal.
They also come in different colours, but the most irritating is the green one that is also so stubborn and won’t go despite one’s numerous attempts to chase it away.
A fly can kill your appetite and also demean one’s self-esteem. It can also cause damage to the image of a place. Imagine you have taken your date to a restaurant, and you have to fend off flies as the waiter brings your food. What about a friend from abroad? He or she may go back home with the impression that flies are in charge of restaurants in Botswana. Imagine you walk into a restaurant in the city centre and you are forced to fend off flies for you to enjoy your meal.
However, that experience is nothing compared to discovering a dead fly in your food whilst eating. What do you do in that situation?
Do you go back to the store or food vendor to lodge a complaint? Do you take out the dead fly and continue to eat your food? What do you do?
Kobamelo Kgalaeng, a student at Limkokwing University of Creative Technology says she has never encountered a fly in food she bought from a restaurant, but would definitely take the food back if that happened. However, she says if the same happened at home, she would simply take out the dead fly and continue to eat her food.
“Because we expect restaurants to be more hygienic than ourselves, and that one would incur expenses if you were to throw away the whole pot of meat for a fly,” she says.
A street vendor who preferred not to be named, who does her business at the Bus Rank market admitted that on several occasions she has found a dead fly in the food she serves the public but just took it out and threw it away.
“Why should you throw away a full pot of beef for a fly? We have co-existed with flies and have never heard of a person dying because of a fly. No, it is only the people of this new generation who think that flies can kill humans. When we were growing up we would take off dead flies from milk and drink it,” she said.
Some of the flies will literally embarrass you. You are walking in a street and the fly keeps nagging you doing rounds around your face. You try to fend it off but it just won’t go away.
But what is this animal that is so irritating, how does it survive?
According to Ofentse Sithole, an antomologist at Ministry of Agriculture there are many species of flies found in Botswana, although a comprehensive study has never been conducted to establish that.
He said that there are six common fly species that are classified as Flies of Public Health Importance. Their lifespan varies between one and three weeks.
“In my 12-year experience with insects, I have encountered at least six common fly species that are classified as Flies of Public Health Importance,” he said.
He said that the fly life expectancy is determined by the temperature, humidity and availability of food and may vary from one to four weeks: The common species are Musca domestica : 2-4 weeks; Sarcophaga pachtyli : Larviposition (birth to larvae/maggots) to adulthood generally takes around two weeks; Chrysomya chloropyga :1-3 weeks; Piophila casei:1-2 weeks; Hippobosca rufipes:3-4 weeks; Chrysomya albiceps:1-2 weeks
Sithole said that the most common and very interactive with human beings is the Musca domestica (Diptera:Muscidae). This is the housefly, which feeds on various liquids, human food and excrement-transmits various diseases like cholera, salmonellosis, typhoid and poliomyelitis;
Another common species is the Sarcophaga pachtyli (Diptera:Sarcophagidae) -- Flesh fly: Gives birth to active larvae(=Ovoviviparity: maggots develop inside eggs and remain in the mother’s body until they are ready to hatch), which is commonly found when there is meat.
Among other species, Sithole said, there is the Chrysomya albiceps (Diptera: Calliphoridae) -- Banded blowfly.
“The Banded blowfly is one of the first flies to appear on a corpse and utilise this food source by laying eggs in the nostrils and other moist body openings,” he said. “In summer the maggots target the soft tissue from a corpse within one week. Chrysomya albiceps can spread anthrax.”
There are other diseases that flies can transmit, such as diarrhoea, Typhoid, Hepatitis A &E, Cholera, and Dysentery. Flies can also transmit allergies.
There are very limited means one can engage to control flies such as domestic sprays, fly catcher and others. But such are used indoors. Flies lay eggs where they spend time.
“It is not necessary to always use chemicals to control flies. Sometimes mechanical/physical methods are sufficient to deter the flies, for example use of fly screens and cages, commercially baited flytraps and most importantly good hygiene and proper disposal of faeces.
Sithole added that indoor chemical sprays should be used as the last resort because most of the sprays contain active ingredients which are harmful to humans e.g. Pyrethroids, Organophosphates.
“Also repeated and deliberate use of these chemical sprays may lead to the well documented insecticide resistance,” he added.
He suggested that the use of Ultra Violet fly traps - (Flies are most attractive to UV light between 350 and 370 nm in wavelength, most noticeably at 365 nm. This UV peak falls in the middle of the Ultra Violet A (UVA) spectrum. Ultraviolet fly traps are safer to use than indoor sprays).