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Global Morbidity and Mortality of Leptospirosis: A Systematic Review.

Costa F, Hagan JE, Calcagno J, Kane M, Torgerson P, Martinez-Silveira MS, Stein C, Abela-Ridder B, Ko AI - PLoS Negl Trop Dis (2015)

Bottom Line: 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 (R(2) = 0.60) of the variation in observed disease incidence.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.

View Article: PubMed Central - PubMed

Affiliation: Oswaldo Cruz Foundation, Brazilian Ministry of Health, Salvador, Bahia, Brazil; Institute of Collective Health, Federal University of Bahia, UFBA, Salvador, Brazil; Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, Connecticut, United States of America.

ABSTRACT

Background: Leptospirosis, 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 findings: We 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 (R(2) = 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/significance: Leptospirosis 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.

No MeSH data available.


Related in: MedlinePlus

Mean relative risk for membership in age and gender groups among leptospirosis cases (A) and deaths (B).Mean and standard deviation of the relative risks are presented for males (blue bars) and females (red bars).
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pntd.0003898.g004: Mean relative risk for membership in age and gender groups among leptospirosis cases (A) and deaths (B).Mean and standard deviation of the relative risks are presented for males (blue bars) and females (red bars).

Mentions: Among the 35 studies that reported information on case fatality ratios (S3 Table); the mean case fatality ratio was 6.85% (95% CI 5.66–8.03). Ten studies reported age- and gender-stratified data for leptospirosis cases (listed in S5 Table). Adults and males had a greater risk for leptospirosis than children and females (S6 Table and Fig 4A), with highest risk (RR, 2.4, 95% CI 0.7–4.1) occurring among adult males with 20–29 years of age. Among three studies with age- and gender-stratified data for deaths from leptospirosis (S5 Table), the age-specific risk for death was different from that for disease (S6 Table and Fig 4B), and the highest risk for death occurred in an older age group of males with 50–59 years of age (RR, 3.7, 95% CI 2.6–4.8). Among 10 studies that reported information on the completeness of laboratory confirmation procedures, paired samples were obtained from a mean of 53% of cases (range, 20–88%). A total of 19 and four studies reported data on both clinically-suspected and laboratory-confirmed cases and deaths, respectively, due to leptospirosis (S7 Table). Among these studies, the mean ratio of clinically-suspected to laboratory-confirmed cases and deaths was 3.1 (95% CI 1.2–5.1) and 2.2 (95% CI, 0.9–3.3), respectively.


Global Morbidity and Mortality of Leptospirosis: A Systematic Review.

Costa F, Hagan JE, Calcagno J, Kane M, Torgerson P, Martinez-Silveira MS, Stein C, Abela-Ridder B, Ko AI - PLoS Negl Trop Dis (2015)

Mean relative risk for membership in age and gender groups among leptospirosis cases (A) and deaths (B).Mean and standard deviation of the relative risks are presented for males (blue bars) and females (red bars).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4574773&req=5

pntd.0003898.g004: Mean relative risk for membership in age and gender groups among leptospirosis cases (A) and deaths (B).Mean and standard deviation of the relative risks are presented for males (blue bars) and females (red bars).
Mentions: Among the 35 studies that reported information on case fatality ratios (S3 Table); the mean case fatality ratio was 6.85% (95% CI 5.66–8.03). Ten studies reported age- and gender-stratified data for leptospirosis cases (listed in S5 Table). Adults and males had a greater risk for leptospirosis than children and females (S6 Table and Fig 4A), with highest risk (RR, 2.4, 95% CI 0.7–4.1) occurring among adult males with 20–29 years of age. Among three studies with age- and gender-stratified data for deaths from leptospirosis (S5 Table), the age-specific risk for death was different from that for disease (S6 Table and Fig 4B), and the highest risk for death occurred in an older age group of males with 50–59 years of age (RR, 3.7, 95% CI 2.6–4.8). Among 10 studies that reported information on the completeness of laboratory confirmation procedures, paired samples were obtained from a mean of 53% of cases (range, 20–88%). A total of 19 and four studies reported data on both clinically-suspected and laboratory-confirmed cases and deaths, respectively, due to leptospirosis (S7 Table). Among these studies, the mean ratio of clinically-suspected to laboratory-confirmed cases and deaths was 3.1 (95% CI 1.2–5.1) and 2.2 (95% CI, 0.9–3.3), respectively.

Bottom Line: 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 (R(2) = 0.60) of the variation in observed disease incidence.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.

View Article: PubMed Central - PubMed

Affiliation: Oswaldo Cruz Foundation, Brazilian Ministry of Health, Salvador, Bahia, Brazil; Institute of Collective Health, Federal University of Bahia, UFBA, Salvador, Brazil; Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, Connecticut, United States of America.

ABSTRACT

Background: Leptospirosis, 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 findings: We 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 (R(2) = 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/significance: Leptospirosis 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.

No MeSH data available.


Related in: MedlinePlus