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

Nogueira, Diogo Pupo; Costa, Flávia Teresa Ribeiro da; Bezerra, Camila de Sousa; Silva, Maria Luana Cristiny Rodrigues; Costa, Diego Figueiredo da; Viana, Maira Pôrto; Silva, José Dêvede da; Júnior, João Pessoa Araújo; Malossi, Camila Dantas; Ullmann, Leila Sabrina; Santos, Carolina de Sousa Américo Batista; Alves, Clebert José; Azevêdo, Sérgio Santos de

doi:10.1016/j.actatropica.2020.105497

Cited by 24 publications

(20 citation statements)

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“…were detected in sheep slaughtered in a semi‐arid region of northeastern Brazil (Silva et al, 2019) and the importance of genital transmission route was later reinforced (Nogueira et al . 2020). Similarly, chronic infection by Leptospira sp.…”

Section: Resultsmentioning

confidence: 99%

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An overview on the molecular diagnosis of animal leptospirosis

Azevedo

Lilenbaum

2021

Lett Appl Microbiol

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The most common presentation of animal leptospirosis is the subclinical and silent chronic form, that can lead to important reproductive disorders. The diagnosis of this chronic form remains a challenge. The aim of the present study is to gather and critically analyse the current information about molecular tools applied to animal leptospirosis diagnosis, particularly the silent chronic presentation of the infection. Regarding clinical specimens, samples from urinary tract were the most used (69/102, 67·7%), while few studies (12/102, 11·8%) investigated samples from reproductive tract. Concerning the molecular methods applied, the most used is still the conventional polymerase chain reaction (PCR) (46/102, 45%), followed by real‐time PCR (38/102, 37·2%). The lipL32 gene is currently the most common target used for Leptospira detection, with 48% of studies applying this genetic marker. From all the studies, only few (21/102, 20·5%) performed gene sequencing. According to the majority of authors, current evidence suggests that lipL32‐PCR is useful for an initial screening for Leptospira DNA detection in animal clinical samples. Posteriorly, if DNA sequencing could be performed on positive lipL32‐PCR samples, we encourage the use of secY gene as a genetic marker. The molecular methods appear as the most important tools for the diagnosis of the chronic silent leptospirosis on domestic animals, reinforcing its evident impact not only on animal reproduction but also on a One Health context.

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Section: Resultsmentioning

confidence: 99%

“…2014; Nogueira et al . 2020) and swine (Fernandes et al . 2020), sexual transmission should not be neglected.…”

Section: Introductionmentioning

confidence: 99%

An overview on the molecular diagnosis of animal leptospirosis

Azevedo

Lilenbaum

2021

Lett Appl Microbiol

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“…In this study, it was possible to observe seropositivity statistically equal in states with different geographic characteristics, as Maranhão is located on the transition between Cerrado and Amazônia, presenting a great variety of ecosystems and biodiversity, Alagoas presents annual precipitation of 400 mm to 2200 mm (Barros et al, 2012), and the cities studied have semi-arid characteristics and smaller levels of precipitation. This corroborates the thesis that leptospirosis is no longer a disease of flooded areas and that it might be present in many herds in northeast Brazil, even in hostile environments, drought periods, capable of surviving even in the presence of higher titers of serology in dry periods, needing active surveillance and reinforcing in the acting of preventive veterinary medicine, due to the zoonotic potential of the disease and the laboral hazard in the acting of professionals such as vets, breeders, and slaughterhouse workers (Dorjee et al, 2008;Adler & De La Peña Moctezuma, 2010;Nogueira et al, 2020).…”

Section: Discussionmentioning

confidence: 99%

“…Goats are less susceptible to leptospirosis than other species, such as cattle and dogs (Martins & Lilenbaum, 2014), presenting fewer clinical signs; however, they end up hosting the agent and even spreading the disease reproductively in the semiarid climate, as rated by Silva et al (2018) and Nogueira et al (2020) in research with sheep, this causes the bacteria to remain in the environment, posing a risk to the population and animals, especially in intercropping.…”

Section: Introductionmentioning

confidence: 99%

Epidemiological survey for goat leptospirosis in two distinct biomes in Northeastern Brazil

Viana

Silva

Lima

et al. 2021

RSD

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Caprine breeding is a largely exploited activity in Brazil, with a herd of over 10 million goats concentrated mostly in the Northeast region, which contains 93.9% of the national herd. However, this region is affected by huge losses due to inappropriate management and illness occurrence, such as leptospirosis, a reproductive disease that causes economic and productive losses. Considering these previous statements, we aimed to determine the most frequent seroprevalence, serogroups and factors associated with the occurrence of leptospirosis in goats from different states and biomes of the Brazilian northeast and properly locate the disease throughout the region through the analysis of epidemiological questionnaires and geographic data. The samples were submitted to the Microscopic Agglutination Test (MAT) with a cutoff of 50. In addition, geographic data were analysed to create maps with epidemiological descriptions of the disease in the states. The total occurrence of seropositive animals was 19.93% (119/597), 18.92% (35/185) in the state of Alagoas and 20.38% (84/412) in Maranhão. The most common serogroups in these states were Autumnalis (31.09%) and Icterohaemorrhagiae (23.81%). Dividing the results, it was possible to observe a greater occurrence of the serogroup Autumnalis (42.86%) Icterohaemorrhagiae (28.57%) in the state of Alagoas, Caatinga biome, plus Autumnalis (26.19%) and Icterohaemorrhagiae (23.81%) in the state of Maranhão, Cerrado biome. It was proven that Leptospira sp. is present in both states and biomes analyzed, present in diverse areas as in vegetation and climate, warning preventive care towards the disease.

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“…This is the first seroepidemiological investigation of leptospirosis in sheep using a planned sampling that is representative of the herds and animals in the Northeast region of Brazil obtained from 7 of the 8 states in that region. The majority of previous studies were localized serological surveys or had small isolated samplings per state [23,27].…”

Section: Discussionmentioning

confidence: 99%

Spatial Distribution of Serologically Reactive Sheep to Leptospira spp. in the Northeast Region of Brazil

Silva

Viana

Calado

et al. 2021

Acta Scientiae. Vet.

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Background: Considering the importance of leptospirosis in sheep farming and public health and the significance of identifying which serogroups circulate in sheep within each region, the objective of this study was to determine the seroprevalence and spatial distribution of the most frequent serogroups causing infection by Leptospira sp. in ovine herds in the Northeast region of Brazil.Materials, Methods & Results: Blood samples were collected from 4197 sheep from 229 herds in 7 Northeastern States. Sera were analyzed via microscopic agglutination test (MAT). The frequency of seroreactive sheep for Leptospira sp. was 14.06%. The states of Alagoas, Ceará, Paraíba, Piauí, Rio Grande do Norte, and Sergipe, located in the Caatinga biome, had the highest frequencies of serologically reactive sheep, and Maranhão, in the Cerrado biome, had the lowest frequency. The most frequent serogroups were Autumnalis (19.49%), Australis (15.76%) and Serjoe (14.41%). In the states of Ceará, Paraíba, Rio Grande do Norte, and Sergipe, 100% of their municipalities had at least one seroreactive animal. The highest frequencies of seropositive animals were found in the municipalities of União (50%), Passagem (49.06%), Canindé (48.89%), Igaci (28.95%), Gararu (31.2%), Pirapemas (17.5%), and Angicos (16%) located in the states of Piauí, Paraíba, Ceará, Alagoas, Sergipe, Maranhão and Rio Grande do Norte, respectively.Discussion: The animal-level prevalence (14.06%) obtained in the present study is significant, especially considering the rustic nature of the species and the adverse conditions of the region for the infectious agent. In semi-arid conditions, it has been suggested that perhaps sheep do not seroconvert detectable titers on MAT with a cut-off point of 1:100. It is important to highlight that theovine population in the Northeast region of Brazil is composed of mixed animals, which have been considered more resistant to infection by Leptospira spp. Also, environmental factors hostile to the survival of the infectious agent in the studied region should be taken into consideration, since they may have influenced the seropositive animal-level prevalence. A noteworthy variation was observed in agglutinin titers, which ranged from 100 to 1,600, where 80.2% of the positive samples had titers ≤ 200. It is important to highlight that more elevated titers (≥ 400) were obtained in all seven states, which may suggest an acute infection caused by a non-adapted serovar, indicating that preventive and control measures focused on possible infection sources for sheep should be adopted. Although some states showed the same serogroups as the most frequent, a variety of serogroups was observed in municipalities, which may indicate different sources of infection, whether interspecies, intraspecies, or via alternative routes of transmission in semi-arid conditions, such as venereal. This indicates that even though sheep are more resistant to infection, they become exposed due to the environment or management conditions. As such, identification, isolation, and treatment of the affected animals are alternative measures recommended for prevention and control of leptospirosis in sheep in the semi-arid region. It is evident that despite the lack of rain observed in the last decade in the Northeast region of Brazil, which prevented the formation of favorable environments for the presence of Leptospira, the infectious agent remains among the sheep, as well as other production and wild animals in the region. Some factors may be contributing to this scenario, such as the fact that sheep farming in the region is characterized mainly by subsistence systems, where veterinary assistance and adequate sanitary management are absent, thus increasing the possibility of contact with Leptospira.Keywords: small ruminants, semi-arid, zoonosis.

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

Cited by 24 publications

References 44 publications

An overview on the molecular diagnosis of animal leptospirosis

An overview on the molecular diagnosis of animal leptospirosis

Epidemiological survey for goat leptospirosis in two distinct biomes in Northeastern Brazil

Spatial Distribution of Serologically Reactive Sheep to Leptospira spp. in the Northeast Region of Brazil

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