Global Morbidity and Mortality of Leptospirosis: A Systematic Review

Abstract

BackgroundLeptospirosis, a spirochaetal zoonosis, occurs in diverse epidemiological settings and affects vulnerable populations, such as rural subsistence farmers and urban slum dwellers. Although leptospirosis is a life-threatening disease and recognized as an important cause of pulmonary haemorrhage syndrome, the lack of global estimates for morbidity and mortality has contributed to its neglected disease status.Methodology/Principal FindingsWe conducted a systematic review of published morbidity and mortality studies and databases to extract information on disease incidence and case fatality ratios. Linear regression and Monte Carlo modelling were used to obtain age and gender-adjusted estimates of disease morbidity for countries and Global Burden of Disease (GBD) and WHO regions. We estimated mortality using models that incorporated age and gender-adjusted disease morbidity and case fatality ratios. The review identified 80 studies on disease incidence from 34 countries that met quality criteria. In certain regions, such as Africa, few quality assured studies were identified. The regression model, which incorporated country-specific variables of population structure, life expectancy at birth, distance from the equator, tropical island, and urbanization, accounted for a significant proportion (R2 = 0.60) of the variation in observed disease incidence. We estimate that there were annually 1.03 million cases (95% CI 434,000–1,750,000) and 58,900 deaths (95% CI 23,800–95,900) due to leptospirosis worldwide. A large proportion of cases (48%, 95% CI 40–61%) and deaths (42%, 95% CI 34–53%) were estimated to occur in adult males with age of 20–49 years. Highest estimates of disease morbidity and mortality were observed in GBD regions of South and Southeast Asia, Oceania, Caribbean, Andean, Central, and Tropical Latin America, and East Sub-Saharan Africa.Conclusions/SignificanceLeptospirosis is among the leading zoonotic causes of morbidity worldwide and accounts for numbers of deaths, which approach or exceed those for other causes of haemorrhagic fever. Highest morbidity and mortality were estimated to occur in resource-poor countries, which include regions where the burden of leptospirosis has been underappreciated.

Estimating Burdens of Neglected Tropical Zoonotic Diseases on Islands with Introduced Mammals

“…These studies include incidence estimates for some islands, the majority of which have large populations. Our estimates for predicted and extrapolated incidence of leptospirosis were similar to some of those developed by Costa and others 27 (Supplemental Table 12). Unfortunately, we could not compare our estimates of T. gondii burden because we calculated seroprevalence estimates for the 31-to 40-year old age-group, whereas Torgerson and Mastroiacovo 13 examined incidence of congenital toxoplasmosis.…”

“…Three recent studies have developed estimates of countrywide incidence for rabies, 26 congenital toxoplasmosis, 13 and leptospirosis, 27 to guide surveillance, vaccination, and reservoir control programs. These studies include incidence estimates for some islands, the majority of which have large populations.…”

“…Although there has been a considerable effort to estimate the global burden of neglected zoonotic diseases such as rabies, 26 congenital toxoplasmosis, 13 and leptospirosis, 27 very little is known about the burden of zoonotic diseases transmitted by introduced mammals on islands. Only a fraction of the 560 islands where people co-occur with introduced mammal host populations 7 has information on disease burdens for any zoonotic disease.…”

Emerging Infectious Disease Implications of Invasive Mammalian Species: The Greater White-Toothed Shrew (Crocidura russula) Is Associated With a Novel Serovar of Pathogenic Leptospira in Ireland

“…Pathogenic species of Leptospira cause leptospirosis, a bacterial zoonotic disease with a global distribution affecting over one million people annually[4, 5]. Leptospires colonize the renal tubules of reservoir hosts, from where they are excreted via urine into the environment and survive in suitable moist conditions.…”

Avaliação e caracterização de candidatos vacinais voltados para o controle da leptospirose.

“…Acredita-se que o número de casos de leptospirose no mundo é muito maior do que a organização mundial de saúde estima. É possível que mais de um milhão de novas infecções por ano possam acontecer, resultando em cerca de 60 mil mortes (COSTA et al, 2015). A prevalência da doença está delimitada às regiões Sul e Sudeste da Ásia, Oceania, Caribe, África, Oriente Subsaariano e regiões Andina, Central e…”