More than 1 million people contract a tropical disease known as leptospirosis each year, resulting in nearly 59,000 deaths, a new study shows.
That worldwide estimate of the impact of the illness, which typically affects underdeveloped areas in Latin America, Africa, Asia and island nations, is far greater than previously thought, the Yale School of Public Health researchers noted.
“The study identified an important health burden caused by this life-threatening disease, which has been long neglected because it occurs in the poorest segments of the world’s population,” study leader Albert Ko, chair of the department of epidemiology of microbial disease at Yale, said in a news release from the New Haven, Conn.-based university.
“At present, there are no effective control measures for leptospirosis. The study provides national and international decision makers with the evidence to invest in initiatives aimed at preventing the disease, such as development of new vaccines,” Ko added.
Spirochetal bacteria, which is found in the urine of rats and other mammals, causes leptospirosis. The germ can survive in soil and water, infecting people through cuts and scrapes on the skin. In developing countries, leptospirosis can lead to bleeding in the lungs and kidney failure.
The researchers said their estimates are likely conservative since people with leptospirosis are often misdiagnosed with malaria, dengue or other illnesses.
To calculate the global toll of the disease, the team analyzed morbidity and mortality studies and databases. Of all diseases that pass between animals and humans, leptospirosis is one of the leading causes of illness and death, the study published Sept. 17 in the journal PLOS Neglected Tropical Diseases found.
As climate change affects global temperatures and urbanization accelerates, the study authors said, the prevalence of leptospirosis will likely rise.
Epidemics of the illness in urban slums are triggered when these areas, which have poor sanitation and inadequate sewage systems, experience severe weather and heavy rainfall. The researchers projected that the world’s slum population will double by 2030, reaching 2 billion people.
The U.S. Centers for Disease Control and Prevention provides more information on the leptospirosis.