Rodents
Certain rodents have spread all over the world due to travel and trade. They are not only found in the tropics from where they originate, but also in the colder climates. It is here that they have been living around people and their homes. Some species live permanently in homes while others come in once it has become cold. Buildings with lack of protection provide an open invitation for rodents to come in, nest and search for food.
We have three main rodents species in South Africa:
The Norway Rat (Rattus Norvegicus)
The Norway rat is fairly large, measuring in at around 330-470mm in length. It weighs upto 500g and has a stub nose with small ears and eyes and a short scruffy coat. The fur on its back is brown and stomach is grey to white with a short tail.
This rat is not a fussy eater as it will happily eat large quantities of meat in one sitting, drinks water and any food with a high water content.
It is not a very agile rat and will only climb if necessary. It swims very well and has a very large territory, upto 100m big. The Norway rat is sexually mature in 2-3 months. It will have 8-12 pups in a litter and upto 7 litters a year. The life expectancy of this rat 9-12 months.
The Black Rat (Rattus Rattus)
This rat is thinner and smaller than the Norway Rat. It weighs upto 200g with a pointy nose, large ears and eyes. It also has a long tail (longer than its head and tail together) smooth coat that is grey to black in colour.
The Black rat eats mostly vegetable foods and can eat large amounts in one sitting. It can go a long time without water. The black rat is agile and likes to climb as it is a very good climber. It does not like water and tries to avoid it but is a good swimmer.
It has a territory of between 15-30 meters. The Black rat is sexually mature in 2-3 months. It has 6-10 offspring per litter and upto 6 litters a year. The life expectancy is 9-12 months.
The House Mouse (Mus musculus)
The house mouse is small and thin and weighs upto only 15g. It has a pointy nose and large ears with small eyes and a long tail.
The house mouse prefers grain and eats only small amounts at a time. It generally draws water from its foods.
This mouse is quite agile and a very good climber. It can swim and has a small territory, about 3-6 meters though it is highly territorial.
It is sexually mature in 1.5 months and has around 5-6 pups in a litter. They can have upto 8 litters per year. The life expectancy of the house mouse is 9-12 months.
Fleas
Fleas are generally a problem in all areas except dry areas of the country. The common species found in buildings is the cat flea (Ctenocephalides felis). They attack cats, humans, dogs, chickens etc. The dog flea and the human flea are less commonly found.
Fleas are small, wingless insects that appear flat in order to pass through the hairs of the host animal more easily. They pass through 4 stages in development. These stages are egg, larva, pupa and adult.
The female lays about 25 eggs a day for about 3 weeks. She lays them on the host, its bed or nest. The eggs hatch in 2-12 days. The perfect temperature range for hatching is between 18-26 degrees Celsius with a humidity level of around 70%. Dry conditions with temperatures over 35 degrees Celsius is deadly to the eggs since they lose too much moisture. The larvae take 8-21 days to develop however; in unfavourable conditions it may take upto 200 days. They feed on the dried blood excreted by the adults. The young adults that have not yet had their first blood meal appear small and black in colour, after they have consumed the blood they become larger and turn a lighter shade of brown.
The pupal stage of the flea usually take 1-2 weeks but if no host is present it can last a year. Adult fleas emerge from the pupal phase depending on the warmth, vibrations and carbon monoxide from the animal. As soon as the adult flea emerges from the pupa, they look for their host and their first blood meal. They can survive 1-2 months without a meal or 7-8 months with one.
Treatment
There are a few things one can do to control fleas. Vacuuming regularly will keep infestations low as the eggs will be continuously picked up. The vibrations from the vacuum will make the adults emerge from the pupal phase only to be sucked up. Vacuuming cannot however get rid of the larvae as they coil themselves around the carpet fibres but it will pick up the dried blood that they feed on thus starving them. The dust in the bag blocks the fleas’ ability to breathe but to be sure vacuum up a tablespoon of cornstarch.
Steam cleaning carpets is another way to control fleas as the heat will kill most adult fleas and larvae as well as a few eggs. The steam though will stimulate some eggs to hatch from the warmth and fleas may appear after a day or two but regular vacuuming should pick this up and it should represent the last of the population.
It is important to ensure that pets are regularly treated to prevent fleas.
Flea spraying for an infestation is regularly used by pest control services. It is important to note that when having a flea spray done, all animals should be removed from the property and washed and dipped to avoid them re-introducing the fleas.