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Field and experimental symptomless infections support wandering donkeys as healthy carriers of Trypanosoma vivax in the Brazilian Semiarid, a region of outbreaks of high mortality in cattle and sheep.

Rodrigues CM, Batista JS, Lima JM, Freitas FJ, Barros IO, Garcia HA, Rodrigues AC, Camargo EP, Teixeira MM - Parasit Vectors (2015)

Bottom Line: None of these signs were observed in donkeys.However, T. vivax from wandering donkeys shared identical or highly similar genotypes (identified by Cathepsin L sequences) with isolates from cattle and sheep outbreaks of acute disease in the Semiarid.Therefore, farmers, veterinaries and control programmes should be aware of healthy carrier donkeys as a possible source of T. vivax for susceptible livestock species in the Brazilian Semiarid.

View Article: PubMed Central - PubMed

Affiliation: Departamento de Parasitologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, SP, Brazil. cmonadeli@usp.br.

ABSTRACT

Background: The Brazilian Semiarid is the home of the largest herd of donkeys in South America and of outbreaks of Trypanosoma vivax infection of high mortality in dairy cattle and sheep. For a comprehensive understanding of the underlying mechanisms of these outbreaks and epidemiological role of donkeys, we surveyed for T. vivax in wandering donkeys and follow the experimental infection of donkeys and sheep with a highly virulent isolate from the Semiarid.

Methods: Blood samples from 180 randomly selected wandering donkeys from the Brazilian Semiarid region were employed for PCV and parasitemia assessments and tested using the T. vivax-specific TviCATL-PCR assay. PCR-amplifed Cathepsin L (CATL) sequences were employed for genotyping and phylogenetic analysis. Four wandering donkeys were experimentally infected with a T. vivax isolate obtained during an outbreak of high mortality in the Semiarid; the control group consisted of two non-inoculated donkeys.

Results: We detected T. vivax in 30 of 180 wandering donkeys (16.6 %) using TviCATL-PCR. The prevalence was higher during the dry (15.5 %) than the wet season (1.1 %) and more females (23.1 %) than males (8.9 %) were infected. All the PCR-positive donkeys lacked patent parasitemia and showed normal values of body condition score (BCS) and packed cell volume (PCV). To evaluate the probable tolerance of donkeys to T. vivax, we inoculated five donkeys with a highly virulent isolate (TviBrRp) from the Semiarid. All inoculated donkeys became PCR-positive, but their parasitemia was always subpatent. A control goat inoculated with TviBrRp showed increasing parasitemia concurrently with fever, declining PCV, tachycardia, mucous membrane pallor, enlarged lymph nodes and anorexia. None of these signs were observed in donkeys. However, T. vivax from wandering donkeys shared identical or highly similar genotypes (identified by Cathepsin L sequences) with isolates from cattle and sheep outbreaks of acute disease in the Semiarid.

Conclusions: This is the first report of T. vivax in donkeys in Brazil and, to our knowledge, the first experimental infection of donkeys with T. vivax. The symptomless field and experimental infections corroborated that donkeys are more tolerant to T. vivax than other livestock species as shown in African countries. Therefore, farmers, veterinaries and control programmes should be aware of healthy carrier donkeys as a possible source of T. vivax for susceptible livestock species in the Brazilian Semiarid.

No MeSH data available.


Related in: MedlinePlus

Epidemiological survey of T. vivax in wandering donkeys from the Brazilian Semiarid using TviCATL-PCR. Association analyses of T.vivax prevalence in wandering donkeys from the state of Rio Grande do Norte (RN) was not statically significant with a age (years), b packed cell volume (PCV) and c body condition score (BCS) but was with d sex (p = 0.014) and e season (dry and wet months) when donkey blood samples were collected (p = 0.000)
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Fig2: Epidemiological survey of T. vivax in wandering donkeys from the Brazilian Semiarid using TviCATL-PCR. Association analyses of T.vivax prevalence in wandering donkeys from the state of Rio Grande do Norte (RN) was not statically significant with a age (years), b packed cell volume (PCV) and c body condition score (BCS) but was with d sex (p = 0.014) and e season (dry and wet months) when donkey blood samples were collected (p = 0.000)

Mentions: We examined blood samples from 180 wandering donkeys captured on the roadways of the RN State in the Brazilian Semiarid. All samples were negative by MH and microscopic analyses. In contrast, species-specific TviCATL-PCR [30] revealed 30 donkeys (16.6 %) that were positive for T. vivax (Fig. 2; Additional file 1). Although the blood samples from several animals generated weakly amplified DNA bands, positive results were corroborated by additional PCRs using DNA preparations from other aliquots of donkeys blood samples. Sequencing of amplified DNA from selected samples (~25 %) confirmed the diagnosis. In previous studies, the most sensitive method used to detect T. vivax in donkeys consisted of initial PCR for whole genome amplification (WGA) followed by species-specific PCR, thus increasing the detection level of T. vivax above the threshold of any conventional PCR [11].Fig. 2


Field and experimental symptomless infections support wandering donkeys as healthy carriers of Trypanosoma vivax in the Brazilian Semiarid, a region of outbreaks of high mortality in cattle and sheep.

Rodrigues CM, Batista JS, Lima JM, Freitas FJ, Barros IO, Garcia HA, Rodrigues AC, Camargo EP, Teixeira MM - Parasit Vectors (2015)

Epidemiological survey of T. vivax in wandering donkeys from the Brazilian Semiarid using TviCATL-PCR. Association analyses of T.vivax prevalence in wandering donkeys from the state of Rio Grande do Norte (RN) was not statically significant with a age (years), b packed cell volume (PCV) and c body condition score (BCS) but was with d sex (p = 0.014) and e season (dry and wet months) when donkey blood samples were collected (p = 0.000)
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4625931&req=5

Fig2: Epidemiological survey of T. vivax in wandering donkeys from the Brazilian Semiarid using TviCATL-PCR. Association analyses of T.vivax prevalence in wandering donkeys from the state of Rio Grande do Norte (RN) was not statically significant with a age (years), b packed cell volume (PCV) and c body condition score (BCS) but was with d sex (p = 0.014) and e season (dry and wet months) when donkey blood samples were collected (p = 0.000)
Mentions: We examined blood samples from 180 wandering donkeys captured on the roadways of the RN State in the Brazilian Semiarid. All samples were negative by MH and microscopic analyses. In contrast, species-specific TviCATL-PCR [30] revealed 30 donkeys (16.6 %) that were positive for T. vivax (Fig. 2; Additional file 1). Although the blood samples from several animals generated weakly amplified DNA bands, positive results were corroborated by additional PCRs using DNA preparations from other aliquots of donkeys blood samples. Sequencing of amplified DNA from selected samples (~25 %) confirmed the diagnosis. In previous studies, the most sensitive method used to detect T. vivax in donkeys consisted of initial PCR for whole genome amplification (WGA) followed by species-specific PCR, thus increasing the detection level of T. vivax above the threshold of any conventional PCR [11].Fig. 2

Bottom Line: None of these signs were observed in donkeys.However, T. vivax from wandering donkeys shared identical or highly similar genotypes (identified by Cathepsin L sequences) with isolates from cattle and sheep outbreaks of acute disease in the Semiarid.Therefore, farmers, veterinaries and control programmes should be aware of healthy carrier donkeys as a possible source of T. vivax for susceptible livestock species in the Brazilian Semiarid.

View Article: PubMed Central - PubMed

Affiliation: Departamento de Parasitologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, SP, Brazil. cmonadeli@usp.br.

ABSTRACT

Background: The Brazilian Semiarid is the home of the largest herd of donkeys in South America and of outbreaks of Trypanosoma vivax infection of high mortality in dairy cattle and sheep. For a comprehensive understanding of the underlying mechanisms of these outbreaks and epidemiological role of donkeys, we surveyed for T. vivax in wandering donkeys and follow the experimental infection of donkeys and sheep with a highly virulent isolate from the Semiarid.

Methods: Blood samples from 180 randomly selected wandering donkeys from the Brazilian Semiarid region were employed for PCV and parasitemia assessments and tested using the T. vivax-specific TviCATL-PCR assay. PCR-amplifed Cathepsin L (CATL) sequences were employed for genotyping and phylogenetic analysis. Four wandering donkeys were experimentally infected with a T. vivax isolate obtained during an outbreak of high mortality in the Semiarid; the control group consisted of two non-inoculated donkeys.

Results: We detected T. vivax in 30 of 180 wandering donkeys (16.6 %) using TviCATL-PCR. The prevalence was higher during the dry (15.5 %) than the wet season (1.1 %) and more females (23.1 %) than males (8.9 %) were infected. All the PCR-positive donkeys lacked patent parasitemia and showed normal values of body condition score (BCS) and packed cell volume (PCV). To evaluate the probable tolerance of donkeys to T. vivax, we inoculated five donkeys with a highly virulent isolate (TviBrRp) from the Semiarid. All inoculated donkeys became PCR-positive, but their parasitemia was always subpatent. A control goat inoculated with TviBrRp showed increasing parasitemia concurrently with fever, declining PCV, tachycardia, mucous membrane pallor, enlarged lymph nodes and anorexia. None of these signs were observed in donkeys. However, T. vivax from wandering donkeys shared identical or highly similar genotypes (identified by Cathepsin L sequences) with isolates from cattle and sheep outbreaks of acute disease in the Semiarid.

Conclusions: This is the first report of T. vivax in donkeys in Brazil and, to our knowledge, the first experimental infection of donkeys with T. vivax. The symptomless field and experimental infections corroborated that donkeys are more tolerant to T. vivax than other livestock species as shown in African countries. Therefore, farmers, veterinaries and control programmes should be aware of healthy carrier donkeys as a possible source of T. vivax for susceptible livestock species in the Brazilian Semiarid.

No MeSH data available.


Related in: MedlinePlus