Seroprevalence and risk factors for leptospirosis in cattle, sheep, and goats at consorted rearing from the State of Piauí, northeastern Brazil

Metabolic and productive parameters of lactating dairy cows under heat stress conditions supplemented with plant polyphenol extract

The impact of heat stress on dairy cattle leads to significant economic losses and a negative impact on the welfare of the animals. The objective of this research was to evaluate the effect of the nutritional additive (Thermoplus®) in dairy cows under postpartum heat stress conditions, and its effects on the metabolic profile, production and quality of milk. Eighteen lactating Holstein cows (8 multiparous and ten primiparous), in a free-stall system, with a mean body condition score (BCS) of 3.14 ± 0.05, live weight of 624.55 ± 18, 61 kg, with initial mean days in milk (DIM) of 90 ± 10.11, were selected. The animals were grouped into a control (CG, n = 9) and a treatment (TG, n = 9). Both groups underwent 14 days of diet adaptation, the TG received the basal diet supplemented with 50 g of the additive, once a day, individually, while the control group received only the total diet. Data collection of metabolic and productive parameters were evaluated on days -14 (before adaptation), 1 (after the diet adaptation period), 16, 30, and 44. Milk, blood, and body condition score (BCS) were collected once a day, and heart rate, respiratory rate, and rectal temperature were collected twice a day. Serum concentrations of albumin, calcium, magnesium, glucose, gamma-glutamyl transferase (GGT), beta-hydroxybutyrate (BHBA), non-esterified fatty acids (NEFAs), and paraoxonase-1 (PON-1) were evaluated. In the milk, the percentage of fat, protein, lactose, and total solids were determined in each sampling. Milk yield was measured daily. Humidity and ambient temperature values were collected on the days of the collection every 30 min, from 5:30 am to 5:00 pm, to calculate the temperature-humidity index (THI). Statistical analyzes were performed using the SAS software (version 9.3, SAS Institute Inc., Cary, NC, USA). The THI ranged from 62.22 to 79.47. Our findings showed that when the THI was greater than 72, the animals in the TG were able to maintain milk yield (Odds ratio (OD) = -0.0577,), and the animals in the CG had a greater chance of reducing it (OD = -0.2301). Multiparous cows in the TG had higher milk yield than CG (32.57 ± 0.34 vs 30.50 ± 0.36 kg per day; P = 0.0078) and lower SCC (34.110 ± 6,940 vs 665.50 ± 214.41 cells per ml; P = 0.03), with the same percentages of total solids (P > 0.05). In multiparous metabolic markers, TG when compared CG had higher albumin concentrations (2.50 ± 0.07 vs 2.12 ± 0.07 g/dl; < 0.001), equal PON-1 (P > 0.05), and higher BHBA levels (0.49 ± 0.03 vs 0.39 ± 0.04 mmol/l). Primiparous from the CG had higher concentrations of NEFA (0.18 ± 0.02 mmol/l) than multiparous from the same group (0.09 ± 0.02 mmol/l) P = 0.0265. The use of the plant polyphenol extract in postpartum Holstein cows challenged by heat stress had beneficial effects on the production and health of the mammary gland in multiparous cows without decreasing milk solids. The non-reduction of the activities of the acute phase proteins indicates an immunomodulatory and inflammatory-reducing effect of the product used.

LipL41 and LigA/LigB Gene Silencing on a LipL32 Knockout Leptospira interrogans Reveals the Impact of Multiple Mutations on Virulence

Leptospirosis is a global zoonosis caused by pathogenic bacteria of the genus Leptospira. The application of the CRISPR/Cas9 system has facilitated the generation of mutants and subsequent evaluation of phenotypes. Since DNA breaks induced by RNA-guided Cas9 nuclease are lethal to Leptospira, different methodologies were implemented to overcome this limitation. Initially, CRISPR interference (CRISPRi) was employed to create knockdown mutants, utilizing a catalytically inactive Cas9 (dCas9). Subsequently, the co-expression of CRISPR/Cas9 and a DNA repair system from Mycobacterium smegmatis enabled the generation of scarless knockout mutants. We eliminated plasmids from the lipL32 knockout L. interrogans strain and further achieved multiple gene mutations via gene silencing in this knockout background. Strains lacking both LipL41 and LipL32 and LigA, LigB, and LipL32, were evaluated. The absence of proteins LipL32 and LipL41 had no effect on leptospiral virulence. On the other hand, mutants lacking LigA, LigB, and LipL32 were unable to cause acute disease. The expanded apparatus for genetic manipulation of pathogenic leptospires via the CRISPR/Cas9 system has allowed the evaluation of multiple mutations upon leptospiral virulence. This work shows that LipL32 and LipL41 are not required for acute disease and consolidates LigA and LigB proteins as virulence factors.

Identification of Pathogenic Leptospira kirschneri Serogroup Grippotyphosa in Water Voles (Arvicola terrestris) from Ruminant Pastures in Puy-de-Dôme, Central France

Rodents are the primary reservoirs for pathogenic Leptospira species, which cause leptospirosis. Among the key potential carriers are water voles, whose population outbreaks can consequently pose a major threat to human and animal health. We studied the prevalence, prominence, and epidemiology of pathogenic Leptospira species in water voles in central France. First, 46 voles were captured, and DNA was extracted from kidney, lung, liver, blood, and urine and tested for the presence of Leptospira using three molecular methods: PCR, O-antigen typing, and variable number tandem repeat (VNTR) typing. We also attempted to culture leptospires from kidney and urine samples. In addition, we investigated leptospiral antibodies in serum samples from 60 sheep using microscopic agglutination testing. These animals co-occurred with the voles, so we sought to assess their degree of exposure and involvement in pathogen dynamics. The overall prevalence of infection was 76.1% (CI_95% [61.2%, 87.4%]). The only strain found was L. kirschneri serogroup Grippotyphosa and a similar VNTR profile was acquired. Leptospires were successfully cultured from kidney and urine samples for four voles. Three sheep had low antibody titers against the Leptospira serogroup Grippotyphosa. Taken together, our results suggest the exclusive carriage of L. kirschneri serogroup Grippotyphosa among water voles in central France. Nevertheless, their ability to act as reservoir hosts that transmit the pathogen to co-occurring livestock remains unclear and merits further research.

Occurrence of IgG antibodies against Toxoplasma gondii, Neospora caninum, and Leptospira spp. in goats and sheep from an indigenous village in Pernambuco, Brazil

This study aimed to determine the occurrence of anti-Toxoplasma gondii, Neospora caninum, and Leptospira spp. antibodies in sheep and goats raised in villages of the Xukuru do Ororubá indigenous community, Pernambuco, Brazil. A total of 180 serum samples from sheep and 108 serum samples from goats of both sexes and different ages were analyzed. For antibody research, indirect immunofluorescence antibody test (IFAT) were used for the protozoa T. gondii and N. caninum, and microscopic agglutination test (MAT) for Leptospira spp., with a cutoff titer of 1:64, 1:50 and 1:100, respectively. The frequency of anti-T. gondii antibodies was 16.6% (30/180) for sheep and 11.1% (12/108) for goats. The frequency of anti-N. caninum antibodies was 10.55% (19/180) for sheep, and 20.37% (22/108) for goats, while for Leptospira spp., 2.2% (4/180) of sheep and 1.85% (2/108) of goats reacted positively. The results obtained in this study are unprecedented in indigenous communities in the country and serve as an alert for monitoring goats and sheep from the Xukuru do Ororubá indigenous village regarding the occurrence and productive impact of infections by T. gondii, N. caninum, and Leptospira spp., in addition to the occurrence of the zoonosis toxoplasmosis and leptospirosis in the indigenous community.

The role of small ruminants in the epidemiology of leptospirosis

Leptospirosis is a common global zoonotic disease of man and all farm animals. Although most leptospiral infections in sheep and goats are asymptomatic, they may play a role in the epidemiology of the disease by the spread of Leptospira through the urine. This study was carried out to evaluate the role of sheep and goats in the epidemiology of leptospirosis. Blood and urine samples were taken from 210 goats and 246 sheep. To detect antibodies, sera samples were tested with 8 live serovars of L. interrogans (Hardjo, Pomona, Grippotyphosa, Canicola, Ballum, Icterhemorrhagiae, Tarasovi, and Australis) by MAT. Then, urine samples were tested by Nested PCR targeting 16S rRNA gene for detection of pathogenic Leptospira. Results of MAT showed that 10.95% of goats and 8.53% of sheep had antibodies against at least one examined serovars. In both species, the highest reacting was L. i. Pomona with a rate of 68.18% and 56% in sheep and goats, respectively. Moreover, in PCR, 2 (0.95%) urine samples of goat and 12 (4.87%) urine samples of sheep were positive. All of the MAT positive studied animals were PCR negative and, statistical analysis showed that there was no relationship and agreement between the results of PCR and MAT in sheep (kappa = − 0.07, p > 0.05) and goats (kappa = − 0.02, p > 0.05). Finally, it is concluded that sheep and goats can excrete L. interrogans in the urine and thus transmit them to other animals and humans.

Seroprevalence and risk factors for Leptospira spp. in small ruminants of semi-arid zone in northeastern Colombia

Leptospirosis in small ruminants is an economically important disease that causes important losses by pathologies of the reproductive tract. The present study aimed to estimate the seroprevalence and risk factors associated with Leptospira spp. in small ruminants under traditional husbandry systems. A cross-sectional epidemiological study was carried out in a sample of 1039 animals which included 793 sheep and 245 goats from 49 farms of 10 municipalities of northeastern areas of Colombia. The MAT test using a panel of 13 laboratory serovars was performed to diagnose the Leptospira spp. antibodies in the serum samples of animals. A structured questionnaire was filled in each farm to obtain information on putative risk factors, and its association with Leptospira spp. infection was detected by univariate and multivariate logistic regression. The general seroprevalence showed a rate of 13.9%, the 79.6% of farms showed at least one positive animal, the 14.2% and 0.4% of positive animals showed titers ≥ 1:100 and 1:200, respectively. The seroprevalence in sheep and goats showed a rate of 13.1% and 16.2%, respectively. The most common serovars in positive animals were Autumnalis (3.6%), Tarassovi (3.4%), Bratislava (2.9%), Mini (2.9%), Bataviae (1.4%), Canicola (0.3%), and Grippotyphosa (0.3%). The univariate and multivariate analysis showed as risk factors the absence of housing system (OR = 3.412 CI: 1.347-8.152), the absence of quarantine measures to new animals (OR = 1.371 CI: 0.943-1.978), and the protective factor identified was the use of Toggenburg breed (OR = 0.571 CI: 0.249-1.074). This exploratory study showed the Leptospira spp. positive small ruminants located in the northeastern areas of Colombia with titer associated with chronic and subclinical infection.

Cross-sectional survey for sheep leptospirosis in the northeast region of Brazil

Sheep farming has shown expressive growth, even in the Northeast region of Brazil, with rainfall below expectations in the last decade. This growth has been observed not only in the number of herds, but also in the number of properties involved in sheep farming. Although expressive, the production of small ruminants still presents low levels of performance, mainly due to the occurrence of diseases, which constitute an obstacle to this activity. The aim of this study was to determine the factors associated with the seroprevalence of leptospirosis in sheep in Northeastern Brazil. Blood samples were collected from 3438 sheep in 190 herds from 48 municipalities, belonging to the states of Ceará, Paraíba, Piauí, Rio Grande do Norte and Sergipe. Serological diagnosis was performed using the microscopic agglutination test (MAT). In 76.3 % (95 % CI = 69.79-81.81) of the herds there was at least one animal seropositive for at least one of the Leptospira spp. serogroups and 14.94 % (95 %CI = 13.8-16.18) of the animals were seropositive. The state of Paraíba had the highest herd (95.7 %) and animal (26.6 %) prevalences, followed by Ceará (93.9 % and 23.7 %, respectively). The most frequent serogroups were Autumnalis (18.68 %), Australis (17.9 %) and Pyrogenes (15.18 %). There was no association between the studied variables and the herd-level prevalence of leptospirosis. High herd and animal-level seroprevalences was found for sheep leptospirosis in the semiarid region of Northeastern Brazil, and there is a need to implement control and prevention measures, such as quarantine, serology, vaccination and adequate treatment, in addition to the introduction of proven healthy animals, mainly in the states of Paraíba and Ceará, aiming to reduce the prevalence of disease.

Pathogenic Leptospira spp. Seroprevalence and Herd-Level Risk Factors Associated with Chilean Dairy Cattle

Leptospirosis is a ubiquitous distributed zoonotic infectious disease present in wild and domestic animals. This study aimed to estimate within-herd and herd-level seroprevalence against pathogenic Leptospira spp. in dairy cows from southern Chile and identify risk factors associated with the herd-level status. We used a multi-stage strategy combined with a stratified sample strategy for randomly sampling 147 herds and 4876 lactating cows. We considered as infected a herd with at least one positive reactor to MAT. In addition, an epidemiological survey was applied to the herd's owners and a logistic regression (LR) model was constructed to analyze it. The overall within-herd prevalence was 5.9% (95% CI 4.9-6.8), the overall herd-level prevalence was 42.2% (95% CI 9.2-47.9), and there was variation in both between different herd sizes. L.&nbsp;borgpetersenii serovars Hardjo and Tarassovi and L. interrogans serovar Pomona were the more frequent serovars in non-vaccinated herds. A factor that decreases the risk of a farm being infected was Leptospira vaccine usage (OR = 0.04; 95% CI = 0.02-0.11), and variables that increase risk were using bulls for mating (OR = 3.43; 95% CI = 1.1-10.1) and continuous calving distribution (OR = 3.4; 95% CI = 1.3-8.8). The study's results will contribute to unravelling the infection burden in the main dairy area of the country and designing control strategies.

Seroprevalence and Associated Risk Factors of Leptospira interrogans Serogroup Sejroe Serovar Hardjo in Dairy Farms in and around Jimma Town, Southwestern Ethiopia

A cross-sectional study was conducted on selected dairy farms in and around Jimma town, Oromia, southwestern Ethiopia from November 2019 to May 2020 to determine the seroprevalence of Leptospira interrogans serogroup Sejroe serovar Hardjo (L. hardjo). Furthermore, information was gathered on individual animal and herd level by using pretested semistructured questionnaire to assess associated risk factors. A stratified and simple random sampling procedure was used for the selection of dairy farms and individual animal's, respectively. Indirect enzyme-linked immunosorbent assay (I-ELISA) was used in this study to detect antibody against L. hardjo. Out of 384 animal's sera, 94 animals were seropositive against L. hardjo antibodies. From 77 dairy farms selected for the study, 57 of them were distinguished as positive for L. hardjo. The overall seroprevalence of leptospirosis caused by L. hardjo was 24.48% (95% CI: 20.18%–28.78%) and 74.03% (95% CI: 64.23%–83.82%) at individual animal and farm level, respectively. The result of multilogistic regression analysis revealed that management system (p < 0.05; OR = 4.25 (95% CI: 2.31–7.82)), hygienic status of the farm (p < 0.05; OR = 0.35 (95% CI: 0.20–0.61)), age of animals (p < 0.05; OR = 8.30 (95% CI: 1.87–36.89)), history of abortion (p < 0.05; OR = 8.37 (95% CI: 1.73–40.42)), herd size (p < 0.05; OR = 2.32 (95% CI: 1.17–4.61)), and access of rodents to the farm (p < 0.05; OR = 0.17 (95% CI: 0.03–0.86)) were significantly associated with the occurrence of L. hardjo infection. However, breed, parity, and introduction of new animals to the farm were insignificantly associated (p > 0.05). Management system of the animal, hygienic status of the farm, herd size, age of animals, previous history of abortion, and access of rodents to the farm were identified as potential risk factors of L. hardjo disease occurrence. Thus, limiting rodents contact with cattle and their feed and water as well as good sanitary practices and husbandry management should be undertaken.

Seroprevalence and Distribution of Leptospiral Serovars in Livestock (cattle, Goats, and Sheep) in Flood-prone Kelantan, Malaysia

Introduction

Leptospirosis is a bacterial disease that affects both humans and animals, the occurrence of which increases markedly during and after heavy rainfall and flooding. The aim of this study was to determine the serological prevalence of leptospiral infection in livestock after a voluminous flood in 10 districts of the Malaysian state of Kelantan.

Material and Methods

In December 2014, Kelantan was hit by an extensive flood. A total of 1,728 serum samples were collected from livestock from the state, comprised of 1,024 from cattle, 366 from goats and 338 from sheep, and they were tested using the microscopic agglutination test (MAT).

Results

Altogether, 203 (11.75%; 203/1728; 95% CI: 10.20%–13.30%) of the tested sera were found to be positive serologically. Cattle had the highest prevalence of 14.16% (145/1024), while goats and sheep had 11.20% (41/366) and 5.03% (17/338) respectively. The most frequent serovars detected were Hardjo-bovis (3.70%; 64/1728), Hebdomadis (2.08%; 36/1728) and Pomona (1.04%; 18/1728). There was a statistically significant association (P < 0.05) between livestock that were exposed to the flood and seropositivity.

Conclusion

This study showed that flood is a risk factor that can play a role in the epidemiology of leptospiral infection in livestock.

Investigating the Immunological and Biological Equilibrium of Reservoir Hosts and Pathogenic Leptospira: Balancing the Solution to an Acute Problem?

Leptospirosis is a devastating zoonotic disease affecting people and animals across the globe. Pathogenic leptospires are excreted in urine of reservoir hosts which directly or indirectly leads to continued disease transmission, via contact with mucous membranes or a breach of the skin barrier of another host. Human fatalities approach 60,000 deaths per annum; though most vertebrates are susceptible to leptospirosis, complex interactions between host species and serovars of Leptospira can yield disease phenotypes that vary from asymptomatic shedding in reservoir hosts, to multi-organ failure in incidental hosts. Clinical symptoms of acute leptospirosis reflect the diverse range of pathogenic species and serovars that cause infection, the level of exposure, and the relationship of the pathogen with the given host. However, in all cases, pathogenic Leptospira are excreted into the environment via urine from reservoir hosts which are uniformly recognized as asymptomatic carriers. Therefore, the reservoir host serves as the cornerstone of persistent disease transmission. Although bacterin vaccines can be used to abate renal carriage and excretion in domestic animal species, there is an urgent need to advance our understanding of immune-mediated host–pathogen interactions that facilitate persistent asymptomatic carriage. This review summarizes the current understanding of host–pathogen interactions in the reservoir host and prioritizes research to unravel mechanisms that allow for colonization but not destruction of the host. This information is required to understand, and ultimately control, the transmission of pathogenic Leptospira.

Seroprevalence and risk factors of bovine leptospirosis in the province of Manabí, Ecuador

Leptospirosis is a zoonotic disease with worldwide distribution. The disease affects dairy and beef cattle, causing infertility, abortion, and reduced milk yield. A cross-sectional study was conducted to determine the seroprevalence of leptospirosis in cattle and the associated risk factors in the province of Manabí, Ecuador. Serum samples from 749 animals from 55 cattle herds were analyzed using the microscopic agglutination test (MAT). Animals were considered positive when titers were ≥ 1:100. The association between the potential risk factors and the positive Leptospira result was modeled at both animal and herd level using a generalized linear model with a binomial distribution and logarithmic link. The seroprevalence was 56.21% at the individual level and 98.18% at the herd level. The most prevalent serovars were Pomona (28.57%) and Icterohaemorragiae (22.30%). At the animal level, only the age was associated with leptospirosis seropositivity. Seroprevalence in animals over three years of age was 1.197 (95% confidence intervals (CI), 1.032 - 1.390), higher compared to animals up to three years old. The seroprevalence of Leptospira spp. was higher in farms with no veterinary assistance (PR = 1.209; 95%CI 1.053 - 1.388) and without a vaccination program against Leptospira (PR = 1.399; 95%CI 1.09 - 1.794). In addition, herds from Junín canton had a significantly higher seroprevalence of Leptospira spp (PR = 1.548; 95%CI 1.213 - 1.977) compared to the Bolívar canton, which had the lowest seroprevalence. In conclusion, more than half of the animals were positive to Leptospiraspp, and almost all herds had at least one positive animal. Furthermore, veterinary assistance and vaccination of cattle must be considered as essential aspects of the disease control program.

Use of serological and molecular techniques for detection of Leptospira sp. carrier sheep under semiarid conditions and the importance of genital transmission route

It is possible that there are peculiarities in the epidemiology of leptospirosis in regions with a semiarid climate, where the environment is often adverse, allowing the occurrence of alternative transmission routes. The objective of the work was to generate contributions to the diagnosis and epidemiology of Leptospira sp. infection in sheep reared in semiarid conditions, using serological, molecular and microbiological techniques for diagnosis in dry and rainy seasons. Samples of blood, vaginal fluid, urine, bladder, kidney, uterus, uterine tube, ovary and placenta were collected from 104 sheep (52 animals per season - dry and rainy) slaughtered in the Brazilian semiarid. Diagnostic tests performed were microscopic agglutination test (MAT), polymerase chain reaction (PCR) and bacterial isolation. Anti-Leptospira sp. antibodies were found in 26 (25%) of the animals analyzed by MAT at 1:50 dilution (cut-off 50), while 69 (66.3%) animals had at least one organ/fluid with the presence of Leptospira sp. DNA. Overall, PCR was performed on 758 fragments of organs/fluids from the genital and urinary tracts, and 519 (68.5%) samples tested positive. PCR-positivity was statistically different in dry (46.2%) and rainy (11.5%) seasons for vaginal fluid. It was possible to perform the DNA sequencing in nine samples with 99% similarity to L. interrogans and recovery of viable strains in three samples of vaginal fluid. Regardless of the biological material used in PCR to detect carrier animals and the season, the highest MAT sensitivity values were obtained with cut-off 50 compared to 100. The results obtained indicate that, even in the adverse environmental conditions of the semiarid region, leptospires may survive and propagate by alternative routes of transmission, such as sexual, and the presence of PCR-positive genital tracts in ewes suggests that sexual transmission may play an important role in the epidemiology of the disease in sheep in Brazilian semiarid. In addition, it is suggested the use of titer 50 as cut-off point at serology in semiarid conditions.

On-farm risk factors associated with Leptospira shedding in New Zealand dairy cattle

This study aimed to evaluate risk factors associated with shedding of pathogenic Leptospira species in urine at animal and herd levels. In total, 200 dairy farms were randomly selected from the DairyNZ database. Urine samples were taken from 20 lactating, clinically normal cows in each herd between January and April 2016 and tested by real-time polymerase chain reaction (PCR) using gyrB as the target gene. Overall, 26.5% of 200 farms had at least one PCR positive cow and 2.4% of 4000 cows were shedding Leptospira in the urine. Using a questionnaire, information about risk factors at cow and farm level was collected via face-to-face interviews with farm owners and managers. Animals on all but one farm had been vaccinated against Hardjo and Pomona and cows on 54 of 200 (27%) farms had also been vaccinated against Copenhageni in at least one age group (calves, heifers and cows). Associations found to be statistically significant in univariate analysis (at P < 0.2) were assessed by multivariable logistic regression. Factors associated with shedding included cattle age (Odds ratio (OR) 0.82, 95% CI 0.71–0.95), keeping sheep (OR 5.57, 95% confidence interval (CI) 1.46–21.25) or dogs (OR 1.45, 95% CI 1.07–1.97) and managing milking cows in a single as opposed to multiple groups (OR 0.45, 95% CI 0.20–0.99). We conclude that younger cattle were more likely to be shedding Leptospira than older cattle and that the presence of sheep and dogs was associated with an increased risk of shedding in cows. Larger herds were at higher risk of having Leptospira shedders. However, none of the environmental risk factors that were assessed (e.g. access to standing water, drinking-water source), or wildlife abundance on-farm, or pasture were associated with shedding, possibly due to low statistical power, given the low overall shedding rate.

Seroprevalence and risk factors associated with equineleptospirosis in the metropolitan region of Salvador and Recôncavo Baiano region, Bahia state (NE Brazil)

Equine leptospirosis, although usually asymptomatic, has been associated with recurrent uveitis, abortion, and other systemic signs, constituting a major economic loss in the equine agribusiness sector. The occurrence of anti-Leptospira spp. agglutinins were investigated in 1200 serum samples of horses from 27 municipalities of the Recôncavo Baiano region, Bahia state (NE Brazil), besides the risk factors related to animals and their cattle farms. The microscopic agglutination test (MAT) was performed using 13 serogroups of Leptospira spp. as antigens. From 1200 analyzed equines, 97 (8%) were considered as positive, which obtained titer equal to or higher than 200. In 22 (78.6%) from the 28 properties, at least one animal was detected as seropositive. The most prevalent serogroup in animals, raised in stables, was the Australis (serovar Bratislava) 67%; in mounted police animals was the Sejroe (serovar Wolffi and Hardjobovis) 50%; and equestrian animals was the Australis (serovar Bratislava) 25% and Icterohaemorrhagiae (serovar Copenhageni) 25%. Equine leptospirosis is present in most cattle farms of the region studied. The risk factors of major importance regarded the semi-extensive livestock farming, the land topography of the cattle farm, the contact with animals in neighboring properties, and cohabitation with goats.

Biochemical parameters of blood in cows in latent course of leptospirosis

Changes in the biochemical parameters of blood in cows in the latent course of leptospirosis have been studied by the results of the reaction of microagglutination (RMA). The dynamics of biochemical blood parameters is manifested by hyperproteinemia, dysproteinemia, hemolytic anemia, hyperbilirubinemia, intra- and extrahepatic cholestasis, hyperfermentemia, mineral metabolism disorders, in particular hypocalcemia, hypophosphatemia, indicating the development of hepatopathy which should be classified as hepatocholangitis. It was determined that the pathological process is manifested in all animals for the titer of antibodies to one or another Leptospira serovar. Significant changes from the side of the hepatobiliary system in infested cows for the antibody titer kabura equaling 1:100, polonica 1:200, ballum 1:100, szvajzak 1:100–1:200, bratislava 1:800 and in animals for the titers kabura of 1:100–1:200; polonium 1:100; szvajzak 1:100–1:200; ballum 1:100; bratislava 1:100–1:200. At leptospirosis caused by bratislava and ballum serovars, a disorder of the functional state of the hepatobiliary system, characterized by an increase in the level of total protein, bilirubin, AST, GGTP and ALP activity was diagnosed as the urea, calcium and phosphorus levels in blood decreased. In the case of the latent course of the disease caused by kabura, polonica, szvajzak, ballumand bratislava serovars, a probably higher concentration of bilirubin, activity of aminotransferases (AST and ALAT), GGTP and ALP was determined in comparison to clinically healthy animals. In cows, in the presence of antibody titers kabura 1:100, polonica 1:200, ballum 1:100, szvajzak 1:100–1:200; bratislava 1:800, in 22.2% of cases, we recorded increase in the total protein against the background of dysproteinemia in 50.0–88.9% of animals, and increase in bilirubin in 78.6%, and increase in the activity of blood serum enzymes (AST, ALAT, GGTP, ALP), and also hypocalcemia and hypophosphatemia in 33.3–100.0%. The conducted studies indicate that in latent leptospirosis in cows, in addition to etiotropic therapy, one should include in the protocol the pharmacological correction preparations, which would contribute to the restoration of the functional state of the hepatobiliary system.

Investigation of chronic infection by Leptospira spp. in asymptomatic sheep slaughtered in slaughterhouse

The study aimed to evaluate the histopathological characteristics of renal lesions in chronically infected sheep and with low titers of anti-Leptospira antibodies from a slaughterhouse. In the serological analysis, 24.74% (48/194) presented seroreactivity with a titer equal to or greater than 100. Among these seroreactive sheep, titers of 100 were predominant (58.33%, 28/48), with the highest titer being 1,600 (2.08%, 1/48). Serogroup Sejroe (sv. Hardjo) was the most frequent at 35.42% (17/48). Leptospiral DNA was verified in 4.12% (8/194) of the kidney samples tested, and no urine sample was positive. All the samples corresponded to the pathogenic species L. interrogans. The eight amplicons with 202-nucleotides were identical with two mismatches (presented 100% of identity) using the PCR targeting to secY gene. Histological sections of PCR-positive kidneys were submitted to direct detection by the anti-LipL32 immunohistochemistry (IHC) technique. The Leptospira spp. antigen was evident in 62.5% (5/8) of the kidneys. Positive staining was observed in the cytoplasm of tubular cells and in the form of brownish aggregates that adhered to tubular epithelial cells and projected into the lumen. Inflammatory lymphoplasmacytic infiltrate, ranging from mild to moderate, with multifocal distribution, was the predominant finding in seroreactive animals (33.33%, 16/48). The demonstration of the leptospiral antigen lining the renal tubules through IHC of naturally infected sheep confirmed by PCR characterizes renal colonization in a species with the presence of histological changes compatible with leptospirosis.

Environmental DNA metabarcoding to detect pathogenic Leptospira and associated organisms in leptospirosis-endemic areas of Japan

Leptospires, which cause the zoonotic disease leptospirosis, persist in soil and aqueous environments. Several factors, including rainfall, the presence of reservoir animals, and various abiotic and biotic components interact to influence leptospiral survival, persistence, and pathogenicity in the environment. However, how these factors modulate the risk of infection is poorly understood. Here we developed an approach using environmental DNA (eDNA) metabarcoding for detecting the microbiome, vertebrates, and pathogenic Leptospira in aquatic samples. Specifically, we combined 4 sets of primers to generate PCR products for high-throughput sequencing of multiple amplicons through next-generation sequencing. Using our method to analyze the eDNA of leptospirosis-endemic areas in northern Okinawa, Japan, we found that the microbiota in each river shifted over time. Operating taxonomic units corresponding to pathogenic L. alstonii, L. kmetyi, and L. interrogans were detected in association with 12 nonpathogenic bacterial species. In addition, the frequencies of 11 of these species correlated with the amount of rainfall. Furthermore, 10 vertebrate species, including Sus scrofa, Pteropus dasymallus, and Cynops ensicauda, showed high correlation with leptospiral eDNA detection. Our eDNA metabarcoding method is a powerful tool for understanding the environmental phase of Leptospira and predicting human infection risk.

Bovine leptospirosis in urban and peri-urban dairy farming in low-income countries: a "One Health" issue?

Global trends in urbanization are increasing the spread of neglected zoonotic infections such as leptospirosis, and reducing the number of human cases of leptospirosis is best accomplished by controlling the infection in the animal reservoir. The aim of this study was to determine the seroprevalence of Leptospira borgpetersenii serovar Hardjo and L. interrogans serovar Hardjo (L. Hardjo) exposure and to assess the associated risk factors for infection in small-scale dairy farming in the urban and peri-urban area of Dushanbe, Tajikistan. The true individual seroprevalence among the dairy cows was 13%, and the level of seroprevalence was positively associated with older cows and with communal grazing practices. The study shows that dairy cows are commonly exposed to L. Hardjo in the study region, and this constitutes a public health risk and demonstrates the importance of including urban and peri-urban areas, where large numbers of humans and animals coexist, when investigating zoonotic infections and when planning and implementing control measures for cattle-associated leptospirosis.