Leptospira seroprevalence and risk factors in health centre patients in Hoima District, Western Uganda

Background The burden of human leptospirosis in Uganda is unknown. We estimated the seroprevalence of Leptospira antibodies, probable acute/recent leptospirosis, and risk factors for seropositivity in humans in rural Western Uganda. Methodology and Principal Findings 359 non-pregnant adults visiting the Kikuube and Kigorobya Health Centers were sequentially recruited during March and April 2014. A health history survey and serum were collected from consented participants. Overall, 69% reported having fever in the past year, with 49% reporting malaria, 14% malaria relapse, 6% typhoid fever, 3% brucellosis, and 0% leptospirosis. We tested sera by microscopic agglutination test (MAT) against eight Leptospira serovars representing seven serogroups. Leptospira seroprevalence was 35% (126/359; 95%CI 30.2–40.3%) defined as MAT titer ≥ 1:100 for any serovar. The highest prevalence was against L. borgpetersenii Nigeria (serogroup Pyrogenes) at 19.8% (71/359; 95%CI 15.9–24.4%). The prevalence of probable recent leptospirosis (MAT titer ≥1:800) was 1.9% (95%CI 0.9–4.2%) and uniquely related to serovar Nigeria (serogroup Pyrogenes). Probable recent leptospirosis was associated with having self-reported malaria within the past year (p = 0.048). Higher risk activities included skinning cattle (n = 6) with 12.3 higher odds (95%CI 1.4–108.6; p = 0.024) of Leptospira seropositivity compared with those who had not. Participants living in close proximity to monkeys (n = 229) had 1.92 higher odds (95%CI 1.2–3.1; p = 0.009) of seropositivity compared with participants without monkeys nearby. Conclusions/Significance The 35% prevalence of Leptospira antibodies suggests that exposure to leptospirosis is common in rural Uganda, in particular the Nigeria serovar (Pyrogenes serogroup). Leptospirosis should be a diagnostic consideration in febrile illness and “smear-negative malaria” in rural East Africa

Serovar panel, seroprevalence of <i>Leptospira</i> serovars and serogroups by Microscopic Agglutination Test (titer ≥1:100) among 359 humans sampled in Hoima, Uganda.

<p>Serovar panel, seroprevalence of <i>Leptospira</i> serovars and serogroups by Microscopic Agglutination Test (titer ≥1:100) among 359 humans sampled in Hoima, Uganda.</p

Frequency histogram showing the number of seropositive sera of patients (n = 359) at each MAT titer to different serovars.

<p>Frequency histogram showing the number of seropositive sera of patients (n = 359) at each MAT titer to different serovars.</p

Frequencies of exposure variables, <i>Leptospira</i> seropositivity (any serovar) by exposure variable categories and the bivariable association (odds ratio, OR) between an exposure variable and seropositivity against any serovar (Any) and sv Nigeria (Ni) in 359 participants from Hoima District, Uganda.

<p>Frequencies of exposure variables, <i>Leptospira</i> seropositivity (any serovar) by exposure variable categories and the bivariable association (odds ratio, OR) between an exposure variable and seropositivity against any serovar (Any) and sv Nigeria (Ni) in 359 participants from Hoima District, Uganda.</p

Multivariable logistic regression: significant effects on seroprevalence of <i>Leptospira interrogans</i> Bratislava, <i>L</i>. <i>borgpetersenii</i> Nigeria and of any serovar listed in Table 2 among 359 humans sampled in Hoima, Uganda.

<p>Multivariable logistic regression: significant effects on seroprevalence of <i>Leptospira interrogans</i> Bratislava, <i>L</i>. <i>borgpetersenii</i> Nigeria and of any serovar listed in <a href="http://www.plosntds.org/article/info:doi/10.1371/journal.pntd.0004858#pntd.0004858.t002" target="_blank">Table 2</a> among 359 humans sampled in Hoima, Uganda.</p