Estimated 4.4 million rats in KL

Rats have become a serious problem since they are reservoirs of leptospirosis and other vector borne diseases.  The number of mortality and infections is increasing rapidly as more humans are exposed to rat urine and droppings.

The Ministry of Health reported 62 deaths and 1,418 cases of infection due to leptospirosis. Another common rat related disease in Malaysia could be salmonellosis but there is lack of data on this.

The two most commonly found rodents in residential, commercial and industrial areas in Malaysia are the house rat Rattus rattus and the Norway rat Rattus norvegicus.  The alarming rate of growth in rat population in Malaysia could be attributed to poor sanitation practices and waste management, the rapid rate of urbanization and improper planning of population centres.

Rats living in close proximity of humans pose serious harm to human health, welfare and economy as they carry pathogenic agents and also cause many allergic disorders. Among the main diseases attributed to rats are the bubonic plague, leptospirosis, murine typhus, salmonellosis and rat-bite fever.

Most patients with leptospirosis have been found to come in contact with rat urine before the onset of illness. If leptospirosis is not treated, the patient could develop kidney damage, meningitis (inflammation of the membrane around the brain and spinal cord), liver failure, and respiratory distress.

Rats which frequent rubbish dumps and sewage tanks also contact Salmonella bacteria.  Food, food containers and food preparation area that are contaminated with rat droppings would be the source of salmonellosis.

Salmonellosis is characterized by diarrhea, abdominal cramps, vomiting and nausea, and generally lasts up to seven days. Unfortunately, in the elderly, children or people with depressed immune systems, Salmonella infections are often fatal if they are not treated with antibiotics.

Besides contaminating our foods and carrying diseases, rats are also a menace as they damage our belongings, chew electrical wires, and cause damage to crops.

The standing population of rats in metropolitan Kuala Lumpur is estimated at 4.4 million whilst the Municipal Council of Penang Island (MPPP) reported that 14,639 rats were caught and killed in 2009.  Massive rat hunt and gassing are undertaken by some local authorities but this does not solve the problem. One source of the problem is increasing rat breeding grounds due to lack of hygiene; with food waste and rubbish abound in the surroundings.

The rat population can increase rapidly if control measures are not taken. Rats breed all year round, about four to seven times a year with an average size litter of six to twelve babies. Assuming a female rat has litters four times a year, this can lead to roughly 582 to 954 rats a year. Although the mortality rate is high, the abundance of food in the urban area ensures the survival and expansion of the rat population.

The relevant authorities and local government should pay more attention to the dangers of an expanding rat population. Rats can even be found in high rise buildings and eateries with good housekeeping.  What more in wet markets, food courts and other eateries where rats have a field day.

So how do we control the rat menace? Besides eliminating rat nesting sites and food sources, we should also seal openings that allow rats to enter our premises.  Rearing cats is a good biological control rather than using baits and chemicals.

The general public and food handlers must be educated on the risks posed by rats and to practice good hygiene. To avoid contamination of food with rat droppings or urine, we must prepare food hygienically, wash all cans before opening, wipe the food preparation counter clean and wash all containers before using.

Local authorities must also carry out frequent checks in all eateries and commercial premises where food is stored and sold to ensure no rat infestation.  The pick-up rate for rat-related illnesses should also be improved.

Rats will thrive wherever food is available – especially discarded food.  To keep the rat population in check we must ensure cleanliness and not dump food waste indiscriminately. CAP calls upon the government to address the rat menace urgently for our common good and in view of public health.

Press Statement, 13 October 2010