A serological survey of leptospirosis in cattle of rural communities in the province of KwaZulu-Natal, South Africa

The prevalence and risk factors associated with Leptospira in donkeys in Ngaka Modiri Molema District, North West Province, South Africa

Background and Aim:

Leptospirosis is one of the major emerging global economic and health problems affecting donkeys, thereby reducing their work output. Furthermore, the disease has public health importance because of its zoonotic nature. Despite the significant contribution donkeys make to the national economy, less attention is given to diseases that afflict donkeys and reduce their productivity and performance. A cross-sectional study was conducted to investigate the seroprevalence of Leptospira and identify risk factors associated with the occurrence of the disease among donkeys in the study area.

Materials and Methods:

A questionnaire survey was used to collect the following data: Demographic, environmental, management, and health-related factors. Blood samples were aseptically collected from 365 randomly selected donkeys from 19 villages. The sera were tested using the microscopic agglutination test. Categorical variables were summarized and presented as proportions and their 95% confidence interval (CI). A binary logistic regression model was fitted to the data to identify risk factors associated with Leptospira seroprevalence in donkeys within the study areas.

Results:

The majority of the donkeys (29.6%; n=108/365) were from Mafikeng local municipality, and the rest (19.7%; n=72/365) were from Ratlou. Just over half (58.1%; n=212/365) of the donkeys tested were female, and the remaining (41.9%; n=153/365) were males. In addition, most donkeys (42.7%; n=156/365) were between 6 and 12 years old, followed by those between 0 and 5 years (37%; n=135/365), and only 20.3% (n=74/365) were above 12 years. Out of the donkeys tested, 11.5% (95% CI: 4.86-18.14) donkeys tested positive for Leptospira antibodies. The most common serovar was Bratislava (81%; n=34/42), followed by Tarassovi (19.04%; n=8/42). While gender was positively associated with seroprevalence of the disease (Adjusted Odds Ratio [AOR]=4.88; p=0.0001), the presence of horses (AOR=0.226; p=0.002) and agricultural activities (AOR=0.093; p=0.0001) in the vicinity of the dwellings of the donkeys were negatively associated with Leptospira seropositivity in the study area.

Conclusion:

Findings reported here show that donkeys in the study area are reservoirs for the predominant serovar Bratislava and the less dominant serovar Tarassovi. The gender of the donkey was a risk factor for Leptospira seroprevalence. Further studies are needed to investigate the role of agricultural activities in the vicinity of the dwellings of donkeys on the occurrence of Leptospira in the study area.

Seroepidemiology of Leptospira infection in slaughtered cattle in Gauteng province, South Africa

Leptospirosis is an important economical disease of livestock globally, especially in Asia, the Caribbean, and the African continent. Its presence has been reported in a wide range of livestock. However, information on leptospirosis in South Africa is scanty. We conducted a cross-sectional study in 11 randomly selected abattoirs to determine the seroprevalence and risk factors for leptospirosis in slaughtered cattle in Gauteng province, South Africa. During abattoir visits to selected abattoirs, blood samples were collected from 199 cattle and demographic data obtained on the slaughtered animals. The microscopic agglutination test (MAT) was performed on all sera using a 26-serotype panel using cutoff titer ≥ 1:100. Animal- and abattoir-level risk factors were investigated for their association with seropositivity for leptospirosis. The seroprevalence of leptospirosis in the cattle sampled was 27.6% (55/199). The predominant serogroups detected in seropositive cattle were Sejroe (sv. Hardjo) (38.2%) and Mini sv. Szwajizak) (14.5%) but low to Canicola (sv. Canicola) (1.8%) and Pomona (sv. Pomona) (1.8%). The differences were statistically significant (P < 0.05). Of the five variables investigated, only one (abattoirs) had statistically significantly (P < 0.001) differences in the seroprevalence of leptospirosis among abattoirs. The study documented for the first time in South Africa, the occurrence of serogroups Sejroe (Hardjo bovis strain lely 607), Tarassovi, Hebdomadis, and Medanensis in slaughtered cattle. It was concluded that six of the nine serovars (representing seven serogroups) of Leptospira spp. circulating in cattle population in South Africa are not vaccine serogroups. The clinical, diagnostic, and public health importance of the findings cannot be ignored.

Spatial epidemiological approaches to inform leptospirosis surveillance and control: A systematic review and critical appraisal of methods

Leptospirosis is a global zoonotic disease that the transmission is driven by complex geographical and temporal variation in demographics, animal hosts and socioecological factors. This results in complex challenges for the identification of high-risk areas. Spatial and temporal epidemiological tools could be used to support leptospirosis control programs, but the adequacy of its application has not been evaluated. We searched literature in six databases including PubMed, Web of Science, EMBASE, Scopus, SciELO and Zoological Record to systematically review and critically assess the use of spatial and temporal analytical tools for leptospirosis and to provide general framework for its application in future studies. We reviewed 115 articles published between 1930 and October 2018 from 41 different countries. Of these, 65 (56.52%) articles were on human leptospirosis, 39 (33.91%) on animal leptospirosis and 11 (9.5%) used data from both human and animal leptospirosis. Spatial analytical (n = 106) tools were used to describe the distribution of incidence/prevalence at various geographical scales (96.5%) and to explored spatial patterns to detect clustering and hot spots (33%). A total of 51 studies modelled the relationships of various variables on the risk of human (n = 31), animal (n = 17) and both human and animal infection (n = 3). Among those modelling studies, few studies had generated spatially structured models and predictive maps of human (n = 2/31) and animal leptospirosis (n = 1/17). In addition, nine studies applied time-series analytical tools to predict leptospirosis incidence. Spatial and temporal analytical tools have been greatly utilized to improve our understanding on leptospirosis epidemiology. Yet the quality of the epidemiological data, the selection of covariates and spatial analytical techniques should be carefully considered in future studies to improve usefulness of evidence as tools to support leptospirosis control. A general framework for the application of spatial analytical tools for leptospirosis was proposed.

Seropositivity of Brucella spp. and Leptospira spp. antibodies among abattoir workers and meat vendors in the city of Mwanza, Tanzania: A call for one health approach control strategies

INTRODUCTION

Brucellosis and leptospirosis are among neglected tropical zoonotic diseases particularly in the resource limited countries. Despite being endemic in these countries, there is paucity of information on its magnitude. This study investigated seropositivity of Brucella spp. and Leptospira spp., and associated factors among abattoir workers and meat vendors in the city of Mwanza, Tanzania.

METHODOLOGY

A community based cross-sectional study was conducted in Mwanza city from May to July 2017. Socio-demographic and other relevant information were collected. Detection of Brucella spp. and Leptospira spp. antibodies were done using slide agglutination test and microscopic agglutination test, respectively. Data were analyzed using STATA version 13 Software.

FINDINGS

A total of 250 participants (146 abattoir workers and 104 meat vendors) were enrolled with median age of 31 (IQR: 25-38) years. The overall, seropositivity of Brucella spp. antibodies was 48.4% (95% Cl: 42-54). Seropositivity of B. abortus was significantly higher than that of B. melitensis (46.0%, 95%Cl: 39-52 vs. 23.6%, 95% Cl: 18-28, P<0.001) while seropositivity of both species was 21.2% (95%Cl: 16-26). The seropositivity of Leptospira spp. was 10.0% (95% CI: 6-13) with predominance of Leptospira kirschneri serovar Sokoine which was detected in 7.2% of the participants. Being abattoir worker (OR: 2.19, 95% CI 1.06-4.54, p = 0.035) and long work duration (OR: 1.06, 95%CI: 1.01-1.11, p = 0.014) predicted presence of both B.abortus and B. melitensis antibodies. Only being married (p = 0.041) was significantly associated with seropositivity of Leptospira spp. Primary education was the only factor independently predicted presence of Brucella spp. antibodies among abattoir workers on sub-analysis of occupational exposure. None of factors were found to be associated with presence of Brucella spp. antibodies among meat vendors on sub-analysis.

CONCLUSION

Seropositivity of B.abortus antibodies among abattoir workers and meat vendors is high and seem to be a function of being abattoir worker, having worked for long duration in the abattoir and having primary education. In addition, a significant proportion of abattoir workers and meat vendors in the city was seropositive for Leptospira kirschneri serovar Sokoine. There is a need to consider 'one health approach' in devising appropriate strategies to control these diseases in the developing countries.

Prevalence of Selected Zoonotic Diseases and Risk Factors at a Human-Wildlife-Livestock Interface in Mpumalanga Province, South Africa

A lack of surveillance and diagnostics for zoonotic diseases in rural human clinics limits clinical awareness of these diseases. We assessed the prevalence of nine zoonotic pathogens in a pastoral, low-income, HIV-endemic community bordering wildlife reserves in South Africa. Two groups of participants were included: malaria-negative acute febrile illness (AFI) patients, called febrilers, at three clinics (n = 74) and second, farmers, herders, and veterinary staff found at five government cattle dip-tanks, called dip-tanksters (n = 64). Blood samples were tested using one PCR (Bartonella spp.) and eight antibody-ELISAs, and questionnaires were conducted to assess risk factors. Seventy-seven percent of febrilers and 98% of dip-tanksters had at least one positive test. Bartonella spp. (PCR 9.5%), spotted fever group (SFG) Rickettsia spp. (IgM 24.1%), Coxiella burnetii. (IgM 2.3%), and Leptospira spp. (IgM 6.8%) were present in febrilers and could have been the cause of their fever. Dip-tanksters and febrilers had evidence of past infection to Rickettsia spp. (IgG 92.2% and 63.4%, respectively) and C. burnetii (IgG 60.9% and 37.8%, respectively). No Brucella infection or current Bartonella infection was found in the dip-tanksters, although they had higher levels of recent exposure to Leptospira spp. (IgM 21.9%) compared to the febrilers. Low levels of West Nile and Sindbis, and no Rift Valley fever virus exposure were found in either groups. The only risk factor found to be significant was attending dip-tanks in febrilers for Q fever (p = 0.007). Amoxicillin is the local standard treatment for AFI, but would not be effective for Bartonella spp. infections, SFG rickettsiosis, Q fever infections, or the viral infections. There is a need to revise AFI treatment algorithms, educate medical and veterinary staff about these pathogens, especially SFG rickettsiosis and Q fever, support disease surveillance systems, and inform the population about reducing tick and surface water contact.

A study of leptospirosis in South African horses and associated risk factors

Most leptospiral infections in horses are asymptomatic; however, acute disease manifestations as well as reproductive failure and recurrent uveitis have been reported. In South Africa, the epidemiology of the disease in horses is not well documented. A serosurvey to determine what serovars were present in horses from Gauteng, KwaZulu-Natal and Western Cape Provinces and to get an estimate of the seroprevalence of leptospirosis was carried out from January 2013 until April 2014 with the assistance of four large equine hospitals located in these provinces. Furthermore, associations between potential risk factors and both seropositive horses to the predominant serovar Bratislava and to Leptospira spp. were statistically evaluated using univariate analysis and multivariable logistic regression models. A total of 663 horse sera were collected and tested against a panel of 24 leptospiral serovars using the microscopic agglutination test. The most predominant serovars in Gauteng were Bratislava [32%, 95% CI: 29-35%]; Djasiman [10.4%, 95% CI: 8-12%] and Arborea [8.9%, 95% CI: 7-11%], in the Western Cape Province, Bratislava [27.35%, 95% CI: 23-32]; Djasiman [15.4%, 95% CI: 12-19%] and Arborea [14.5%, 95% CI: 11-18%] and in KwaZulu-Natal, Bratislava [39.4%, 95% CI: 34-44%]; Arborea [9.6%, 95% CI: 7-13%]; and Tarassovi [7.7%, 95% CI: 5-10%] respectively. Twenty one serovars representing 17 serogroups were detected with serovar Bratislava being the most serodominant. The apparent prevalence to one or more serovars of Leptospira spp. at a serum dilution of 1:100 in Gauteng, KwaZulu-Natal and Western Cape Provinces were 49%; 37% and 32% respectively. The true prevalence was calculated for each province taking into account the clustering effect during the sampling and was found to be between 24 and 74% in Gauteng; 26-39% in the Western Cape and 20-54% in KwaZulu-Natal. Nooitgedacht (South African horse breed) horses were found to be at greater risk of being seropositive to both serovar Bratislava (OR=5.08) and Leptospira spp. (OR=6.3). Similarly, horses residing on properties with forestry in the vicinity were found to be at greater risk of being seropositive to both serovar Bratislava (OR=9.3) and Leptospira spp. (OR=5.2). This study has shown that a high proportion of horses in South Africa are exposed to a wide range of serovars, inferring a complex epidemiology. It also describes for the first time new serovars of Leptospira in South African horses that have not previously been reported.

Circulating serovars of Leptospira in cart horses of central and southern Ethiopia and associated risk factors

Little work has been done on diseases of horses in Ethiopia or tropical regions of the world. Yet, Ethiopia has the largest horse population in Africa and their horses play a pivotal role in their economy as traction animals. A serological and questionnaire survey was therefore conducted to determine the circulating serovars of Leptospira and their association with potential risk factors in the cart horse population of Central and Southern Ethiopia. A total of 184 out of 418 cart horses from 13 districts had antibody titres of 1:100 or greater to at least one of 16 serovars of Leptospira species in Central and Southern Ethiopian horses. A significantly higher seropositivity (62.1%) was noted in horses from the highland agroecology followed by midland (44.4%) and lowland (39.8%). Serovar Bratislava (34.5%) was the predominant serovar followed by serovars Djasiman (9.8%), Topaz (5.98%) and Pomona (5.3%). Age and location proved to be associated with seropositive horses with older horses being more commonly affected and the districts of Ziway (Batu) (Apparent Prevalence (AP)=65.5%), Shashemene (AP=48.3%) and Sebeta (AP=41.4%) having the highest prevalence. Multivariable logistic regression found risk factors significantly associated with Leptospira seropositive horses were drinking river water (OR=2.8) and horses 7-12 years old (OR=5) and risk factors specifically associated with serovar Bratislava seropositive horses were drinking river water (OR=2.5), horses ≥13 years (OR=3.5) and the presence of dogs in adjacent neighbouring properties (OR=0.3). Dogs had a protective effect against seropositivity to serovars Bratislava and Djasiman, which may be due to their ability to control rodents. The high seroprevalence confirm that leptospirosis is endemic among horses of Central and Southern Ethiopia. The predominance of serovar Bratislava supports the idea that serovar Bratislava may be adapted to and maintained by the horse population of Central and Southern Ethiopia. This study emphasizes the need for further countrywide serological surveys and isolation of circulating leptospires in animals and humans in order to understand the role of horses in the epidemiology of this disease.

Leptospirosis in cattle: a challenging scenario for the understanding of the epidemiology

All over the world, leptospirosis has been reported as one of the major causes of reproductive failure in cattle and other ruminants, determining abortions, stillbirth, weak newborns and decrease in their growth rate and milk production. Nevertheless, despite its importance, it is still a challenging disease, from what scarce information about epidemiology, prophylaxis and control is available nowadays. During the last decades of the last century, many epidemiological studies have been conducted in several countries, mainly based on serology. According to those studies, a seroepidemiological scenario has been stated for different regions, where different serovars were reported for cattle. Nevertheless, a huge problem is that, when efforts are made in order to increase the collection of local strains (isolates), it has been demonstrated that the scenario that emerges from those studies contrasts with those previously determined by serology. Despite the large number of serological studies worldwide, the number of isolates is scarce. Isolation technique is a very delicate procedure that needs no contamination, fast processing and long delay to produce a positive result, what may corroborate to the lack of information for the comparison between serology versus bacteriological data, mainly in developing countries. It is noteworthy that the epidemiological scenario now acknowledged may not represent what really occurs in many parts of the world, particularly on those tropical regions where the disease is endemic. Consequently, the current knowledge about epidemiology and control, as well as the available diagnostic tools and the commercial vaccines, may not be adequate for those regions, what leads to a frustrating scenario of endemicity and difficulties on the control of the disease. Without a huge effort in the culturing of local strains, besides the advances on molecular typing, leptospirosis will not be defeated and will probably remain endemic in the developing countries, leading to important economic hazards in animal production and risks to public health in those regions.

Characteristics of rural leptospirosis patients admitted to referral hospitals during the 2008 leptospirosis outbreak in Sri Lanka: implications for developing public health control measures

To determine the exposure risk factors of highly endemic rural leptospirosis in tropical setting, we conducted a prospective, hospital-based case control study in Sri Lanka. A conceptual hierarchy of variables was used to analyze the data. Case patients included 38 (34%) females and 73 (66%) males with a mean age of 36 yr (SD 12.7 yr). Using piped, chlorinated water for drinking/general purposes (odds ratio [OR] 0.33, 95% confidence interval [CI] 0.16-0.67), paddy fields in the vicinity of home (OR 1.77, 95% CI 1.06-2.97), sighting dogs at home yard/dog ownership (OR 1.79, 95% CI 1.11-2.91), sighting cattle at home yard/cattle ownership (OR 1.69, 95% CI 1.00-2.84), and work in a paddy field (OR 3.02, 95% CI 1.68, 5.41) were the main predictors of leptospirosis among febrile patients. In high endemic tropical settings with rural leptospirosis, risk factors in residential environments, rather than individual exposures, seemed to play a major role in leptospirosis disease transmission.

Leptospirosis in Sub-Saharan Africa: a systematic review

BACKGROUND

Leptospirosis is an emerging zoonotic infection worldwide, possibly due to climate change and demographic shifts. It is regarded as endemic in Sub-Saharan Africa; however, for most countries scarce epidemiological data, if any, exist. The primary objectives were to describe the prevalence of leptospirosis in countries in Sub-Saharan Africa, and to develop options for prevention and control in the future.

METHODS

A systematic review was conducted to determine the prevalence of leptospirosis in Sub-Saharan Africa; the PRISMA guidelines were followed. Medline/PubMed, Embase, The Cochrane Library, Web of Science, BIOSIS Previews, the African Index Medicus, AJOL, and Google Scholar were searched.

RESULTS

Information about the prevalence and incidence of leptospirosis in humans is available, but remains scarce for many countries. Data are unavailable or outdated for many countries, particularly those in Central Africa. Most data are available from animals, probably due to the economic losses caused by leptospirosis in livestock. In humans, leptospirosis is an important cause of febrile illness in Sub-Saharan Africa. It concerns numerous serogroups, harboured by many different animal carriers.

DISCUSSION

A wide variety of data was identified. Prevalence rates vary throughout the continent and more research, especially in humans, is needed to reliably gauge the extent of the problem. Preventive measures need to be reconsidered to control outbreaks in the future.

Risk factor analysis for antibodies to Brucella, Leptospira and C. burnetii among cattle in the Adamawa Region of Cameroon: a cross-sectional study

Brucellosis, leptospirosis and Q fever are important livestock diseases, commonly responsible for significant production losses, yet their epidemiology in sub-Saharan Africa is largely unknown. Animal reservoirs pose the main risk of transmission to humans, where serious disease can occur. In the developing world setting, the flu-like symptoms of the acute stages of these diseases can be misdiagnosed as malaria, which can result in the administration of the wrong treatment, prolonged disease and increase in antibiotic resistance. Multivariable mixed-effects logistic regression models in this study revealed potential risk factors associated with the aforementioned pathogens in cattle in the Adamawa Region of Cameroon, with wildlife, namely, buffaloes, playing a major role in both Brucella and Coxiella burnetii seropositivity. Cattle mixing with other herds at night and cattle grazing in an area on a route taken by herds on transhumance appear to be positively associated with Leptospira seropositivity, while female cows and whether buffaloes are seen during grazing or transhumance are positively associated with C. burnetii seropositivity. On the other hand, animals that have been on transhumance in the past year and animals belonging to herdsmen of the Fulbe ethnic group appear to be protected against Leptospira and C. burnetii, respectively. Cattle of more than 2 years old appear to have increased odds of being seropositive to either pathogen. Further research is needed to confirm these findings and improve the knowledge of the epidemiology of these three pathogens in Africa, taking particular consideration of the wildlife involvement in the disease transmission.

Commonly used severity scores are not good predictors of mortality in sepsis from severe leptospirosis: a series of ten patients

Introduction. Severe leptospirosis, also known as Weil's disease, can cause multiorgan failure with high mortality. Scoring systems for disease severity have not been validated for leptospirosis, and there is no documented method to predict mortality. Methods. This is a case series on 10 patients admitted to ICU for multiorgan failure from severe leptospirosis. Data were collected retrospectively, with approval from the Institution Ethics Committee. Results. Ten patients with severe leptospirosis were admitted in the Patras University Hospital ICU in a four-year period. Although, based on SOFA scores, predicted mortality was over 80%, seven of 10 patients survived and were discharged from the hospital in good condition. There was no association between SAPS II or SOFA scores and mortality, but survivors had significantly lower APACHE II scores compared to nonsurvivors. Conclusion. Commonly used severity scores do not seem to be useful in predicting mortality in severe leptospirosis. Early ICU admission and resuscitation based on a goal-directed therapy protocol are recommended and may reduce mortality. However, this study is limited by retrospective data collection and small sample size. Data from large prospective studies are needed to validate our findings.

Herd contact structure based on shared use of water points and grazing points in the Highlands of Ethiopia

The use of shared common water points (WPs) and grazing points (GPs) at two different levels of administrative aggregation (village and kebelle) in a region of the Highlands of Ethiopia was explored by means of a questionnaire survey and social network analysis. Despite GPs being more abundant than WPs (208 and 154, respectively), individual GPs provide more contact opportunities for animals. There was great variability in the contact structure of the selected villages within kebelles for both networks, with this variability being higher in the GP networks for each kebelle. Contrary to the commonly held view that WPs are critical for the potential transmission of infectious diseases, intervention at GPs in the Ethiopian Highlands may have greater impact on contacts and thereby opportunities for transmission of infectious diseases between flocks. Some villages appear naturally at much lower risk of introducing disease. These findings could help the design of surveillance and control activities for directly transmitted infectious diseases.