Leptospirosis is a bacterial zoonosis that poses an increasing global public health risk. Pacific Island communities are highly vulnerable to leptospirosis outbreaks, yet the local drivers of infection remain poorly understood. We conducted a systematic review to identify the drivers of human Leptospira infection in the Pacific Islands. There were 42 included studies from which findings were synthesized descriptively. In tropical Pacific Islands, infections were a product of sociodemographic factors such as male gender/sex, age 20 to 60 years, Indigenous ethnicity, and poverty; lifestyle factors such as swimming, gardening, and open skin wounds; and environmental factors, including seasonality, heavy rainfall, and exposure to rodents, cattle, and pigs. Possible mitigation strategies in these islands include strengthening disease reporting standards at a regional level; improving water security, rodent control, and piggery management at a community level; and information campaigns to target individual-level drivers of infection. By contrast, in New Zealand, exposures were predominantly occupational, with infections occurring in meat and farm workers. Accordingly, interventions could include adjustments to occupational practices and promoting the uptake of animal vaccinations. Given the complexity of disease transmission and future challenges posed by climate change, further action is required for leptospirosis control in the Pacific Islands.

Indian Ocean islands are endemic areas for human and animal leptospirosis. Maintenance host species for Leptospira spp. have still not been completely elucidated, and recently the role of cats (Felis catus) has been questioned. This cross-sectional study aims to determine whether cats are part of the maintenance community of different strains of Leptospira spp. in Reunion Island. The prevalence of Leptospira infection in an opportunistic sample of stray and domestic cats (n = 92) from Reunion Island has been studied using serological (microagglutination test) and molecular detection (polymerase chain reaction (PCR)). The results revealed a seroprevalence of 37.0% (34/92) (cut-off 1:40) without a significant difference in the living conditions of animals. The predominant serogroup was Icterohaemorrhagiae, but Ballum, Cynopteri and Australis were also detected. Using PCR, 28.6% (12/42) of stray cats were tested positive. Leptospiral DNA was detected in renal tissue, urine and blood of respectively 14.3% (6/42), 10.3% (4/39) and 11.9% (5/42) of stray cats, but 0% (0/3), 0% (0/50) and 0% (0/36) of domestic cats (P = non-applicable, P = 0,038, P = 0,058 respectively). Partial rrs gene (16S rRNA) sequencing identified Leptospira interrogans in all PCR-positive samples. Our study confirms that renal carriage and urinary shedding are possible, positioning cats, and especially stray cats as potential actors within the maintenance community of L. interrogans in Reunion Island.

Strongyloidiasis and leptospirosis are neglected tropical diseases that have affected many countries across the world. In this study, we evaluated the seroprevalence of Strongyloides stercoralis among patients with leptospirosis in northern Iran. We evaluated 156 laboratory- or clinically confirmed leptospirosis cases. The overall seroprevalence of S. stercoralis was 32.0% (95% confidence interval (CI): 27.4–36.5%, 50/156). Seropositivity was significantly associated with agricultural activities (odds ratio (OR): 2.84, 95% CI: 1.0–8.77) and gastrointestinal disorders (OR: 2.4, 95% CI: 1.1–4.9). Laboratory findings indicated that seropositivity of S. stercoralis was significantly associated with decreased levels of platelet and elevated levels of creatinine, alanine aminotransferase and aspartate aminotransferase (P < 0.05). Our findings suggested a higher exposure to S. stercoralis larvae among patients with leptospirosis. The public health and medical communities may benefit from this research through preventive measures to improve farmers’ knowledge and awareness regarding strongyloidiasis and leptospirosis and the associated risk factors.

Swine can act as asymptomatic carriers of some Leptospira serovars. In this study, 1194 sera from 61 farms located in five different Regions of North-West Italy were collected from slaughtered healthy pigs. Presence of antibody against four Leptospira serovars was evaluated. Overall, 52.5% of analysed farms presented at least one positive animal and 34.4% presented at least one positive swine with titre ⩾1:400. A percentage of 16.6% sera was positive and 5.9% samples presented a positive titre ⩾1:400. Tuscany and Lombardy showed the highest percentage of positive farms (64.3% and 54.6%, respectively) and sera (28.5% and 13.3%, respectively), probably due to environmental conditions and potential risk factors, which promote maintenance and spreading of Leptospira in these areas. The main represented serogroups were Australis (21.3% positive farms, 8.2% positive sera) and Pomona (18.0% positive farms, 8.1% positive sera). In swine, these serogroups are the most detected worldwide; however, our results seem to highlight a reemerging of serogroup Pomona in pigs in investigated areas. A low percentage of sera (0.6%) scored positive to Canicola, leaving an open question on the role of pigs in the epidemiology of this serovar. Higher antibody titres were detected for serogroups Australis and Pomona. Swine leptospirosis is probably underestimated in Italy and could represent a potential risk for animal and human health.

This report describes the effective public health response to a measles outbreak involving a university campus in Brisbane, Australia. Eleven cases in total were notified, mostly university students. The public health response included targeted measles vaccination clinics which were established on campus and focused on student groups most likely to have been exposed. The size of the university population, social interaction between students on and off campus, as well as limited vaccination records for the university community presented challenges for the control of this extremely infectious illness. We recommend domestic students ensure vaccinations are current prior to matriculation. Immunisation information should be included in university student enrolment packs. Incoming international students should ensure routine vaccinations are up-to-date prior to arrival in Australia, thereby reducing the risk of importation of measles and other infectious diseases.

Infectious diseases frequently have multiple potential routes of intraspecific transmission of pathogens within wildlife and other populations. For pathogens causing zoonotic diseases, knowing whether these transmission routes occur in the wild and their relative importance, is critical for understanding maintenance, improving control measures and ultimately preventing human disease. The Norway rat (Rattus norvegicus) is the primary reservoir of leptospirosis in the urban slums of Salvador, Brazil. There is biological evidence for potentially three different transmission routes of leptospire infection occurring in the rodent population. Using newly obtained prevalence data from rodents trapped at an urban slum field site, we present changes in cumulative risk of infection in relation to age-dependent transmission routes to infer which intra-specific transmission routes occur in the wild. We found that a significant proportion of animals leave the nest with infection and that the risk of infection increases throughout the lifetime of Norway rats. We did not observe a significant effect of sexual maturity on the risk of infection. In conclusion, our results suggest that vertical and environmental transmission of leptospirosis both occur in wild populations of Norway rats.

Leptospirosis is a zoonotic disease that the pathogen can be transmitted to humans through the excretions of infected animals. In the Republic of Korea, the Livestock Manure Control Act was enforced in September 2007 to improve underground water hygiene. The objective of this study was to evaluate the impact of Livestock Manure Control Policy on the incidence and the trend of human leptospirosis. An interrupted time series analysis using the monthly incidence of leptospirosis was conducted based on data derived from the Korean National Surveillance System between January 1999 and January 2015. We used a Spearman correlation method to compare the level of leptospirosis incidence decrease between the metropolitan cities and rural provinces. The annual incidence of leptospirosis in South Korea decreased by 33% after policy enforcement of the policy. A significant change in the slope of human leptospirosis cases was observed after the policy enforcement (β = −0·09, P < 0·001). Moreover, we detected a clear association between the size of the rice paddy fields and the decrease in leptospirosis incidence in provinces (r = 0·817, P = 0·01). This study shows that the Livestock Manure Control Policy had significantly reduced human leptospirosis incidence in the Republic of Korea, in particular, in rural regions.

A study was conducted to assess the awareness of cattle abortions due to brucellosis, Rift Valley fever (RVF) and leptospirosis, and to compare frequencies of reported abortions in communities living at the periphery of the Great Limpopo Transfrontier Conservation Area in southeastern Zimbabwe. Three study sites were selected based on the type of livestock–wildlife interface: porous livestock–wildlife interface (unrestricted); non-porous livestock–wildlife interface (restricted by fencing); and livestock–wildlife non-interface (totally absent or control). Respondents randomly selected from a list of potential cattle farmers (N = 379) distributed at porous (40·1%), non-interface (35·5%) and non-porous (26·4%), were interviewed using a combined close- and open-ended questionnaire. Focus group discussions were conducted with 10–12 members of each community. More abortions in the last 5 years were reported from the porous interface (52%) and a significantly higher per cent of respondents from the porous interface (P < 0·05) perceived wildlife as playing a role in livestock abortions compared with the other interface types. The odds of reporting abortions in cattle were higher in large herd sizes (odds ratio (OR) = 2·6; 95% confidence interval (CI) 1·5–4·3), porous (OR = 1·9; 95% CI 1·0–3·5) and non-porous interface (OR = 2·2; 95% CI 1·1–4·3) compared with livestock–wildlife non-interface areas. About 21·6% of the respondents knew brucellosis as a cause of abortion, compared with RVF (9·8%) and leptospirosis (3·7%). These results explain to some extent, the existence of human/wildlife conflict in the studied livestock–wildlife interface areas of Zimbabwe, which militates against biodiversity conservation efforts. The low awareness of zoonoses means the public is at risk of contracting some of these infections. Thus, further studies should focus on livestock–wildlife interface areas to assess if the increased rates of abortions reported in cattle may be due to exposure to wildlife or other factors. The government of Zimbabwe needs to launch educational programmes on public health awareness in these remote areas at the periphery of transfrontier conservation areas where livestock–wildlife interface exists to help mitigate the morbidity and mortality of people from some of the known zoonotic diseases.

Leptospirosis is the most widespread zoonosis in humans worldwide. In the United States, widespread detection of antibodies to leptospirosis have been identified in feral swine (Sus scrofa) with the highest detection of serovars, Bratislava, Icterohaemorrhagiae, and Pomona. Over the past few years, feral swine populations have expanded their geographical range and distribution in the United States with reports in at least 39 of 50 states. Since feral swine serve as reservoirs for serovars that can infect humans, it is important to understand the risk of transmission. In order to learn more about the probability that feral swine shed infectious leptospires, we collected kidneys and paired serum when possible from 677 feral swine in 124 counties of 29 states. These counties had previously been identified as antibody positive for Leptospira interrogans serovars Bratislava, Canicola, Grippotyphosa, Hardjo, Icterohaemorrhagiae or Pomona. Although exposure to these same six serovars of leptospirosis continued to be high (53% overall) in the counties we sampled, we detected leptospiral DNA in only 3·4% of feral swine kidneys tested. Based on these results, it appears that although feral swine can serve as a source of infection to humans, especially in those who are more likely to encounter them directly such as wildlife biologists, veterinarians, and hunters, the risk may be relatively low. However, further studies to examine the relationship between leptospiral shedding in the urine and kidneys in addition to culturing the organism are recommended in order to better understand the risk associated with feral swine.

Dengue fever (DF) and leptospirosis are serious public problems in tropical regions, especially in Manila, the Philippines. In attempting to understand the causes of DF and leptospirosis seasonality, meteorological factors have been suspected, but quantitative correlation between seasonality and meteorological factors has not been fully investigated. In this study, we investigated correlation of temporal patterns of reported numbers of laboratory-confirmed cases of both DF and leptospirosis with meteorological conditions (temperature, relative humidity, rainfall) in Manila. We used time-series analysis combined with spectral analysis and the least squares method. A 1-year cycle explained underlying variations of DF, leptospirosis and meteorological data. There was a peak of the 1-year cycle in temperature during May, followed by maxima in rainfall, relative humidity and number of laboratory-confirmed DF and leptospirosis cases. This result suggests that DF and leptospirosis epidemics are correlated not only with rainfall but also relative humidity and temperature in the Philippines. Quantifying the correlation of DF and leptospirosis infections with meteorological conditions may prove useful in predicting DF and leptospirosis epidemics, and health services should plan accordingly.

Leptospirosis incidence has increased markedly since 1995 in Thailand, with the eastern and northern parts being the most affected regions, particularly during flooding events. Here, we attempt to overview the evolution of human prevalence during the past decade and identify the environmental factors that correlate with the incidence of leptospirosis and the clinical incidence in humans. We used an extensive survey of Leptospira infection in rodents conducted in 2008 and 2009 and the human incidence of the disease from 2003 to 2012 in 168 villages of two districts of Nan province in Northern Thailand. Using an ad-hoc developed land-use cover implemented in a geographical information system we showed that humans and rodents were not infected in the same environment/habitat in the land-use cover. High village prevalence was observed in open habitat near rivers for the whole decade, or in 2008–2009 mostly in rice fields prone to flooding, whereas infected rodents (2008–2009) were observed in patchy habitat with high forest cover, mostly situated on sloping ground areas. We also investigated the potential effects of public health campaigns conducted after the dramatic flood event of 2006. We showed that, before 2006, human incidence in villages was explained by the population size of the village according to the environmental source of infection of this disease, while as a result of the campaigns, human incidence in villages after 2006 appeared independent of their population size. This study confirms the role of the environment and particularly land use, in the transmission of bacteria, emphasized by the effects of the provincial public health campaigns on the epidemiological pattern of incidence, and questions the role of rodents as reservoirs.

We report herein the investigation of a leptospirosis outbreak occurring in triathlon competitors on Réunion Island, Indian Ocean. All participants were contacted by phone or email and answered a questionnaire. Detection and molecular characterization of pathogenic Leptospira was conducted in inpatients and in rodents trapped at the vicinity of the event. Of the 160 athletes competing, 101 (63·1%) agreed to participate in the study. Leptospirosis was biologically confirmed for 9/10 suspected cases either by real-time PCR or serological tests (MAT or ELISA). The total attack rate, children's attack rate, swimmers’ attack rate, and the attack rate in adult swimmers were respectively estimated at 8·1% [95% confidence interval (CI) 4·3–14·7], 0%, 12·7% (95% CI 6·8–22·4) and 23·1% (95% CI 12·6–33·8). Leptospirosis cases reported significantly more wounds [risk ratio (RR) 4·5, 95% CI 1·6–13], wore complete neoprene suits less often (RR 4·3, 95% CI 1·3–14·5) and were most frequently unlicensed (RR 6·6, 95% CI 2·9–14·8). The epidemiological investigation supported that some measures such as the use of neoprene suits proved efficient in protecting swimmers against infection. PCR detection in rats revealed high Leptospira infection rates. Partial sequencing of the 16S gene and serology on both human and animal samples strongly suggests that rats were the main contaminators and were likely at the origin of the infection in humans.

This study assessed seroprevalence and risk factors for Leptospira (serovars Hardjo, Pomona, Ballum, Copenhageni, Tarassovi) exposure in New Zealand veterinarians. Veterinarians (n = 277) at one of two conferences were voluntarily enrolled and blood samples taken. Microscopic agglutination test (MAT) titres ⩾48 were considered seropositive. Fourteen veterinarians (5·1%, 95% confidence interval 2·8−8·3) were seropositive to Leptospira. Home slaughter of cattle or pigs were significant risk factors for Leptospira exposure. There were no clear relationships between the animal species handled at work and serostatus. However, veterinarians spending a ‘mid to high’ proportion of their time (>50% to ⩽75%) with pets had higher odds of being seropositive than those not working with pets. A borderline positive association (P = 0·09) was observed between seropositivity and clinical influenza-like illness (⩾3 days off work) in the 18 months before the study. Assuming causality, this suggests that 8·3% of these cases may be attributed to Leptospira exposure.

A number of recent reports emphasize the risk of zoonotic diseases and the high degree of prevalence of asymptomatic animals infected with Leptospira interrogans. This report sought to assess the prevalence of antibodies to certain serovars of L. interrogans, and to describe the association between seropositivity and risk factors associated with within-flock transmission in a mountainous region of Mexico. Overall seroprevalence to L. interrogans was 54·5% (95% confidence interval 48·3–60·7); the most frequent serovar was Icterohaemorrhagiae. The accumulation of placentas and fetuses at a site close to lambing paddocks can play a significant role as a risk factor for within-flock transmission of L. interrogans in transhumant farming systems in the municipality of Xalatlaco. The high prevalence of L. interrogans antibodies supports the hypothesis that natural foci of this zoonosis are present in sheep flocks in this area. These findings emphasize the need for planning and implementation of control programmes for ovine leptospirosis in Mexico and elsewhere.

Two global (re-)emerging zoonoses, leptospirosis and hantavirus infections, are clinically indistinguishable. Thirty-one patients, hospitalized in Sri Lanka for acute severe leptospirosis, were after exclusion of other potentially involved pathogens, prospectively screened with IgM ELISA for both pathogens. Of these, nine (29·0%) were positive for leptospirosis only, one (3·2%) for hantavirus only, seven (22·5%) for both pathogens concomitantly, whereas 13 (41·9%) remained negative for both. Moreover, in a retrospective study of 23 former patients, serologically confirmed for past leptospirosis, six (26·0%) were also positive in two different IgG ELISA hantavirus formats. Surprisingly, European Puumala hantavirus (PUUV) results were constantly higher, although statistically not significantly different, than Asian Hantaan virus (HTNV), suggesting an unexplained cross-reaction, since PUUV is considered absent throughout Asia. Moreover, RT–PCR on all hantavirus IgM ELISA positives was negative. Concomitant leptospirosis-hantavirus infections are probably heavily underestimated worldwide, compromising epidemiological data, therapeutical decisions, and clinical outcome.

Leptospirosis is a zoonosis of worldwide distribution, caused by infection with pathogenic spirochaetes of the genus Leptospira. The wild boar (Sus scrofa), an important hunting species in Europe, seems to play a significant role in the epidemiological cycle of leptospirosis. A total of 101 serum samples from wild boar hunted in Northern Portugal were analysed for leptospiral antibodies detection by microscopic agglutination test. Sera were collected during hunting seasons (2011–2013) and tested with 17 different pathogenic serovars of Leptospira. Antibodies against nine serovars were detected in 66 (65·4%) of these sera. Serovars Tarassovi and Altodouro exhibited the highest seroreactivity rates (23·8% and 16·8%, respectively), followed by Autumnalis (7·9%) and Bratislava (6·9%). Age and district of origin were found to be risk factors for the presence of leptospiral antibodies in contrast to gender. From a One Health perspective, this study revealed that wild boar should be considered as a potential source of leptospirosis dissemination for humans and animal species (domestic and wild) in shared environments, particularly in the Trás-os-Montes region.

As feral swine continue to expand their geographical range and distribution across the United States, their involvement in crop damage, livestock predation, and pathogen transmission is likely to increase. Despite the relatively recent discovery of feral swine involvement in the aetiology of a variety of pathogens, their propensity to transmit and carry a wide variety of pathogens is disconcerting. We examined sera from 2055 feral swine for antibody presence to six serovars of Leptospira that can also infect humans, livestock or domestic animals. About 13% of all samples tested positive for at least one serovar, suggesting that Leptospira infection is common in feral swine. Further studies to identify the proportion of actively infected animals are needed to more fully understand the risk they pose.

An outbreak of leptospirosis occurred in the South of Belgium, during August 2012, in teenagers who participated in two consecutive adventure scout camps near the Semois river. Among the symptomatic patient population (ten scouts), clinical manifestations included headache (70%), myalgia (50%), fever (50%), bilateral conjunctival injection (50%), general malaise (30%), vomiting (20%), anorexia (20%) and cough (20%). Some of the cases presented elevated blood creatinine (40%), or proteinuria (30%). Three patients were confirmed by serology and one by polymerase chain reaction. Potential risk factors included direct contact with a muskrat and indirect contact with potentially contaminated environments including the river water. Prospective environmental investigation carried out near the river banks 2 weeks after the outbreak identified Ondatra zibethicus (muskrat) as one Leptospira sp. reservoir.

The aims of this study were to determine the annual incidence of infection with Leptospira interrogans serovar Pomona and/or Leptospira borgpetersenii serovar Hardjo and its association with influenza-like illness (ILI) in meat workers in New Zealand. Sera were collected twice, 50–61 weeks apart, from 592 workers at eight abattoirs slaughtering sheep (n = 4), cattle (n = 2) and deer (n = 2), and tested by the microscopic agglutination test for Hardjo and Pomona. Forty-nine (8·3%) participants either seroconverted or had at least a twofold increased serological titre against either serovar. The worker infection risk was higher in sheep abattoirs (11·9%) than in abattoirs processing deer (0%) or cattle (1·2%) (P < 0·01). The annualized risk of mild (ILI) or severe clinical disease attributable to the two Leptospira serovars was 2·7%. This study has demonstrated that meat workers are at substantial risk of infection and clinical disease, suggesting further investigation of infection sources and preventive measures are warranted.