The Leptospirosis Trail

Dark, dirty overflowing water from sewage have been sweeping the streets of Phnom Penh nowadays and even the unpredictable drizzles have managed to bring floods across the city. What’s more disturbing, aside from the health concerns one might acquire due to this erratic weather, are the diseases arising from these floods. 

There is an increased risk of infection of water-borne diseases acquired through direct contact with polluted waters. This includes dermatitis, conjunctivitis and wound infections. However, these are not categorized as epidemic-prone. The only epidemic-prone infection transmitted from direct contact with contaminated water is leptospirosis. Leptospirosis has been known in almost all parts of the world but still the problem about the disease hasn’t been fully addressed especially in developing countries such as Cambodia. the disease has constantly existed in the country over the years. In 2002, a study confirmed the endemicity of the disease in many areas in these countries (Laras K, Cao BV, et al., 2002, The importance of leptospirosis in Southeast Asia.  Am J Trop Med Hyg).

Leptospirosis is a bacterial disease that is transmitted to humans through contact with the urine of infected animals, such as rats, mice, cattles, pigs, horses and even dogs, in surface water. The Leptospira enters the body through broken skin, water-softened skin, mucous membranes (the thin moist lining of many parts of the body such as the nose, mouth, throat and genitals), skin wounds and cuts or by swallowing or inhaling contaminated water.

Epidemiology of Leptospirosis

Carrier animals, domestic or wild, spread leptospires within the population. Leptospires may then be transmitted to humans directly by contact with infected urine or indirectly via contaminated soil or water, especially in times of flood. Human leptospirosis constitutes a dead-end infection; human to human transmission is virtually unknown.

First Phase symptoms present in someone with leptospirosis is almost the same as someone having ordinary flu. This septicemic phase starts abruptly with headache, severe muscular aches, fever to >39° C, chills, cough, sore throat, and sometimes hemoptysis; this phase lasts 4 to 9 days. Second phase symptoms, or the immune symptoms, follow after 1 to 2 weeks and the enormity is different from the first phase—jaundice (yellowing of the skin and eyes), kidney failure, irregular heartbeat, lung problems, and red eyes. Some patients might even develop meningitis or inflammation of the lining of the brain. 

ARE YOU AT RISK?

Leptospirosis is a zoonosis that occurs in many domestic and wild animals (particularly rats) and anyone who is exposed to rats is at risk. In a city where rats are commonly seen whizzing through gutters and canals, there is a huge risk imposed among the populace where bacteria easily penetrate the body most commonly through cuts and scratches. Leptospirosis has often been considered as an occupational disease, but recreational activities and traveling in endemic countries are also recognized as risk factors (Vinetz JM, et al., 1996, Sporadic urban leptospirosis. Ann Intern Med). Significant exposure also occurs from normal daily activities, with high rates of infection during heavy rainfall and flooding (Pappas G, et al., 2008, The globalization of leptospirosis: worldwide incidence trends. Int J Infect Dis). Urban slum dwellers in areas with poor sanitation, an increasing case in the city, are at particularly high risk. 

Social control measures are now being executed by different types of workers such as as farmers, sewer workers, abattoir workers and military personnel. One study suggested that the use of trousers and long skirts among pond cleaners in Thailand is a strong protective factor against infection (Phraisuwan P, et al., 2002, Skin wounds and control strategies, Thailand, Emerging Infectious Diseases). Health education campaigns are also needed to educate and reduce cases since rodents are recognized as the most important reservoirs in the transmission of this disease, therefore the use of rodenticides, entrapment of animals, and improved sanitation is a must to successfully diminish risk of leptospirosis transmission. As such, leptospirosis has always been preventable. 

Common household and personal prevention tips include getting rid of rats. Whenever you have entrapped rats, whether they are dead or not, do not touch them with unprotected hands. Also, wash cuts and grazes immediately with soap and running water and cover all cuts and broken skin with waterproof plasters before and during work. As for rainy seasons, always wear protective clothing and limit yourself from passing through frequently flooded areas. More importantly, wash your hands before eating, drinking or smoking.