Photon-number-resolving segmented avalanche-photodiode detectors

We investigate the feasibility and performance of photon-number-resolved photodetection employing avalanche photodiodes (APDs) with low dark counts. The main idea is to split n photons over m modes such that every mode has no more than one photon, which is detected alongside propagation by an APD. We characterize performance by evaluating the purities of positive-operator-valued measurements (POVMs), in terms of APD number and photon loss.Comment: 5 pages, 7 figures, submitted for publicatio

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

Abstract\ud \ud Background\ud 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.\ud \ud \ud Methods\ud 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.\ud \ud \ud Results\ud 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.\ud \ud \ud Conclusions\ud 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.CNPq and CAPES Brazilian agencies supported this research. CMFR is a PhD\ud fellow of CNPq and HAG and ACR are recipients of post-doctoral fellowships\ud from CNPq (PDJ) and CAPES (PNPD

The phylogeography of trypanosomes from South American alligatorids and African crocodilids is consistent with the geological history of South American river basins and the transoceanic dispersal of Crocodylus at the Miocene

Background: Little is known about the diversity, phylogenetic relationships, and biogeography of trypanosomes infecting non-mammalian hosts. In this study, we investigated the influence of host species and biogeography on shaping the genetic diversity, phylogenetic relationship, and distribution of trypanosomes from South American alligatorids and African crocodilids. Methods: Small Subunit rRNA (SSU rRNA) and glycosomal Glyceraldehyde Phosphate Dehydrogenase (gGAPDH) genes were employed for phylogenetic inferences. Trypanosomes from crocodilians were obtained by haemoculturing. Growth behaviour, morphology, and ultrastructural features complement the molecular description of two new species strongly supported by phylogenetic analyses. Results: The inferred phylogenies disclosed a strongly supported crocodilian-restricted clade comprising three subclades. The subclade T. grayi comprised the African Trypanosoma grayi from Crocodylus niloticus and tsetse flies. The subclade T. ralphi comprised alligatorid trypanosomes represented by Trypanosoma ralphi n. sp. From Melanosuchus niger, Caiman crocodilus and Caiman yacare from Brazilian river basins. T. grayi and T. ralphi were sister subclades. The basal subclade T. terena comprised alligatorid trypanosomes represented by Trypanosoma terena n. sp. from Ca. yacare sharing hosts and basins with the distantly genetic related T. ralphi. This subclade also included the trypanosome from Ca. crocodilus from the Orinoco basin in Venezuela and, unexpectedly, a trypanosome from the African crocodilian Osteolaemus tetraspis. Conclusion: The close relationship between South American and African trypanosomes is consistent with paleontological evidence of recent transoceanic dispersal of Crocodylus at the Miocene/Pliocene boundaries (4–5 mya), and host-switching of trypanosomes throughout the geological configuration of South American hydrographical basins shaping the evolutionary histories of the crocodilians and their trypanosomes.We are grateful to many people who kindly helped us in crocodilian capture\ud and sample collection in Brazil, Venezuela, and Guinea Bissau. We would like\ud to thank Dr. Miguel U. Trefault Rodrigues for the animal identifications. We\ud acknowledge the Brazilian Ministry of Science, Technology and Innovation\ud (MCTI) for support through the Mamirauá Institute for Sustainable\ud Development (IDSM). We thank Cristina Schwartz for the coordination of the\ud work in Guinea Bissau. We also thank Marcio C. Valentin from the Laboratory\ud of Electron Microscopy, Institute of Biosciences, USP, and Carlos E. Jared and\ud Marta M. Antoniazzi from the Institute Butantan, São Paulo, SP, Brazil, for\ud their kindly permission to use their electron microscopic facilities. This work\ud was supported by CNPq (PROAFRICA and PROSUL) and CAPES (Programa\ud Nacional de Incentivo à Pesquisa em Parasitologia Básica). LBV was\ud postdoctoral fellow sponsored by CNPq-MCTI (PROTAX – National Program\ud of Taxonomy) and CAPES (PNPD). BRF is recipient of a scholarship from\ud CNPq (PROTAX)

Microsatellite analysis supports clonal propagation and reduced divergence of Trypanosoma vivax from asymptomatic to fatally infected livestock in South America compared to West Africa

Background: Mechanical transmission of the major livestock pathogen Trypanosoma vivax by other biting flies than\ud tsetse allows its spread from Africa to the New World. Genetic studies are restricted to a small number of isolates\ud and based on molecular markers that evolve too slowly to resolve the relationships between American and West\ud African populations and, thus, unable us to uncover the recent history of T. vivax in the New World.\ud Methods: T. vivax genetic diversity, population structure and the source of outbreaks was investigated through the\ud microsatellite multiloci (7 loci) genotype (MLGs) analysis in South America (47isolates from Brazil, Venezuela and\ud French Guiana) and West Africa (12 isolates from The Gambia, Burkina Faso, Ghana, Benin and Nigeria).\ud Relationships among MLGs were explored using phylogenetic, principal component and STRUCTURE analyses.\ud Results: Although closely phylogenetically related, for the first time, genetic differences were detected between\ud T. vivax isolates from South America (11 genotypes/47 isolates) and West Africa (12 genotypes/12 isolates) with no\ud MLGs in common. Diversity was far greater across West Africa than in South America, where genotypes from Brazil\ud (MLG1-6), Venezuela (MLG7-10) and French Guiana (MLG11) shared similar but not identical allele composition. No\ud MLG was exclusive to asymptomatic (endemic areas) or sick (outbreaks in non-endemic areas) animals, but only\ud MLGs1, 2 and 3 were responsible for severe haematological and neurological disorders.\ud Conclusions: Our results revealed closely related genotypes of T. vivax in Brazil and Venezuela, regardless of\ud endemicity and clinical conditions of the infected livestock. The MLGs analysis from T. vivax across SA and WA\ud support clonal propagation, and is consistent with the hypothesis that the SA populations examined here derived\ud from common ancestors recently introduced from West Africa. The molecular markers defined here are valuable to\ud assess the genetic diversity, to track the source and dispersion of outbreaks, and to explore the epidemiological\ud and pathological significance of T. vivax genotypes.This work was funded through projects within the PROAFRICA and PROSUL programs from the Brazilian agency CNPq. We are grateful to Professor Erney P. Camargo for the joint coordination of these projects and helpful commentaries on the manuscript. HAG was funded by a CDCH-UCV studentship from Venezuela; ACR is a postdoctoral fellow of PNPD-CAPES and CMFR is recipient of PhD scholarships from CNPq-PROTAX. The authors would like to acknowledge for clinical and epidemiological information, blood samples of T. vivax infected livestock and valuable help in the fieldwork several colleagues Garcia et al. Parasites & Vectors 2014, 7:210 Page 11 of 13\ud http://www.parasitesandvectors.com/content/7/1/210 from African countries, Venezuela and Brazil (Galiza GF, Da Silva A and Cadioli L\ud also for previous joint studies). We are grateful to The Wellcome Trust for making available sequences from the genome of T. vivax from Sanger Institute. We are deeply in debt to Wendy Gibson (Bristol University, UK) for helpful discussions and suggestions that much improved our manuscript

High genetic diversity in field isolates of Trypanosoma theileri assessed by analysis of cathepsin L-like sequences disclosed multiple and new genotypes infecting cattle in Thailand

In this study, we describe the first survey in Thailand of Trypanosoma theileri, a widespread and prevalent parasite of cattle that is transmitted by tabanid flies. Investigation of 210 bovine blood samples of Thai cattle from six farms by hematocrit centrifuge technique (HCT) revealed 14 samples with trypanosomes morphologically compatible to T. theileri. Additional animals were positive for T. theileri by PCR based on the Cathepsin L-like sequence (TthCATL-PCR) despite negative by HCT, indicating cryptic infections. Results revealed a prevalence of 26 +/- 15% (95% CI) of T. theileri infection. Additionally, 12 samples positive for T. theileri were detected in cattle from other 11 farms. From a total of 30 blood samples positive by HCT and/or PCR from 17 farms, seven were characterized to evaluate the genetic polymorphism of T. theileri through sequence analysis of PCR-amplified CATL DNA sequences. All CATL sequences of T. theileri from Thai cattle clustered with sequences of the previously described phylogenetic lineages TthI and TthII, supporting only two major lineages of T. theileri in cattle around the world. However, 11 of the 29 CATL sequences analyzed showed to be different, disclosing an unexpectedly large polymorphic genetic repertoire, with multiple genotypes of T. theileri not previously described in other countries circulating in Thai cattle. (C) 2011 Elsevier B.V. All rights reserved.Brazilian agency CNPqConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Centre de Cooperation Internationale en Recherche Agronomique pour le Developpement (CIRAD, France)Centre de Cooperation Internationale en Recherche Agronomique pour le Developpement (CIRAD, France)Thailand International Cooperation Agency (TICA, Bangkok, Thailand)Thailand International Cooperation Agency (TICA, Bangkok, Thailand)Faculty of Veterinary Medicine, Kasetsart University (FVM/KU, Bangkok, Thailand)Faculty of Veterinary Medicine, Kasetsart University (FVM/KU, Bangkok, Thailand)CDCH-UCV in VenezuelaCDCH-UCV in Venezuel

Molecular epidemiological insights into trypanosoma vivax in Argentina: from the endemic Gran Chaco to outbreaks in the pampas

Argentina is a home to millions of beef and dairy cattle and is one of the world's major exporters of meat. In the present study, Trypanosoma vivax was prevalent (2016–2018) in two major livestock farming regions, the Gran Chaco and the Pampas. In the Gran Chaco, 29% and 51% of animals (n = 72, taurine x zebuine crossbreed) were, respectively, positive by TviCATL-PCR and the more sensitive fluorescent fragment length barcoding (FFLB) method. While 18.4/38.8% of breeding cows (n = 49) tested positive by PCR/FFLB, infection increased to 52.2/78.3% in an outbreak of acute infection in steers (n = 23, taurine breed) brought from a non-endemic area. In the Pampas, overall infection rates in dairy cows (n = 54, taurine breed) were comparable (p >.01) between PCR (66.7%) and FFLB (62.9%) and showed a remarkable increase (PCR / FFLB) from 48.3/44.8% in 2017 to 88/84% in 2018. Infected dairy cattle exhibited anaemia, fever, anorexia, enlarged lymph nodes, emaciation and neurological signs. In contrast, beef cows (taurine x zebuine crossbreed) from the Pampas (n = 30) were asymptomatic despite exhibiting 16.7% (PCR) and 53.3% (FFLB) infection rates. Microsatellite genotyping revealed a remarkable microheterogeneity, seven genotypes in the Gran Chaco, nine in the Pampas and five shared between both regions, consistent with regular movement of T. vivax infected livestock. Data gathered in our study support the Gran Chaco being an endemic area for T. vivax, whereas the Pampas emerged as an outbreak area of acute infection in dairy cattle with critical negative impact in milk production. To the best of our knowledge, this is the first molecular study of T. vivax in Argentina, and results indicated the need for preventive measures to control T. vivax spread from the Gran Chaco to vast livestock farming areas across Argentina.Fil: Florentin, Andrea Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones y Transferencia de Formosa. Provincia de Formosa. Centro de Investigaciones y Transferencia de Formosa. Universidad Nacional de Formosa. Centro de Investigaciones y Transferencia de Formosa; ArgentinaFil: Garcia Perez, Herakles A.. Universidade de Sao Paulo; BrasilFil: Rodrigues, Carla M.F.. Universidade de Sao Paulo; BrasilFil: Dubois, Eugenio Fernando. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones y Transferencia de Formosa. Provincia de Formosa. Centro de Investigaciones y Transferencia de Formosa. Universidad Nacional de Formosa. Centro de Investigaciones y Transferencia de Formosa; ArgentinaFil: Monzon, Carlos Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones y Transferencia de Formosa. Provincia de Formosa. Centro de Investigaciones y Transferencia de Formosa. Universidad Nacional de Formosa. Centro de Investigaciones y Transferencia de Formosa; ArgentinaFil: Teixeira, Marta M. G.. Universidade de Sao Paulo; Brasi

Trypanosoma vivax nos tecidos testicular e epididimário de ovinos experimentalmente infectados

Quatro ovinos machos, com cerca de 12 meses de idade (Ovinos 1-4), foram infectados por via intravenosa com aproximadamente 1,25x10(5) tripomastigotas de Trypanosoma vivax, outros quatro ovinos (Ovinos 5-8) destinaram-se ao grupo controle. Após a infecção, exames clínicos visando avaliar temperatura retal, freqüências cardíaca e respiratória e parasitemia foram realizados diariamente por 30 dias, tempo estabelecido para o término do experimento. A avaliação do hematócrito foi realizada a cada cinco dias. Ao final do período experimental, os animais foram castrados e os testículos e epidídimos submetidos ao exame anatomopatológico. Amostras destes órgãos dos Ovinos 1, 4 e 5 foram tomadas para a realização da reação em cadeia da polimerase (PCR). Os parâmetros clínicos (hipertermia, aumento das freqüências cardíaca e respiratória, aumento de volume dos linfonodos e palidez das mucosas) mantiveram-se para o grupo infectado acima dos valores mostrados pelo grupo controle durante todo o período experimental. A parasitemia foi observada a partir do 3º dia pós-infecção (dpi) com picos nos 6-10os dpi e nos 15-18os dpi. Os Ovinos 1 e 4 apresentaram, a partir do 25º dpi, anemia acentuada. Macroscopicamente, todos os testículos dos animais do grupo infectado apresentaram-se flácidos e com coloração pálida. Microscopicamente, observaram-se degeneração testicular moderada a acentuada, epididimite multifocal e hiperplasia do epitélio epididimário. A análise por PCR de T. vivax nos tecidos testicular e epididimário resultou em 100% de positividade para ovinos infectados experimentalmente. As lesões epididimárias e testiculares associadas à presença do parasita nesses órgãos, detectada por PCR, sugerem a participação do parasita no mecanismo etiopatogênico de danos reprodutivos