Genotyping of Brazilian Giardia duodenalis human axenic isolates

Giardia duodenalis is a complex species that comprises at least seven distinct genetic groups (A to G), but only genotypes A and B are known to infect humans and a wide variety of other mammals. Regardless of biological, biochemical and antigenic analysis, several isolates maintained in vitro were not genetically typed yet. So, in the present study, five Brazilian axenic isolates obtained from asymptomatic and symptomatic patients were typed in order to determine the major genetic groups to which the isolates belonged. DNA was extracted from axenic trophozoites, fragments of glutamate dehydrogenase (gdh) and triosephosphate isomerase (tpi) genes were amplified by PCR and the isolate genotyping was carried out using restriction fragment length polymorphism (RFLP) and DNA sequencing for both genes. The results revealed that all isolates were assigned to genotype A at both analyzed loci. Indeed, DNA sequence analysis classified the four isolates obtained from asymptomatic individuals into subtype AII, while the isolate obtained from the symptomatic patient was typed as subtype AI. Despite of the limited number of isolates assessed, the findings presented herein provide interesting insights on the occurrence of Giardia genotypes in Brazil and hold the perspective for future molecular and epidemiological investigations.(AU)

Diagnosis of Giardia infections by PCR-based methods in children of an endemic area

The present study was designed to estimate the prevalence of Giardia infection in preschool- and school-aged children living in an endemic area. Fecal samples from 573 children were processed by zinc sulfate centrifugal flotation, centrifugal sedimentation (using a commercial device for fecal concentration - TF-Test kit®) and polymerase chain reaction (PCR)-based methods. Of the stool samples assessed, 277 (48.3 percent) were positive for intestinal parasites and/or commensal protozoa. Centrifugal flotation presented the highest diagnostic sensitivity for Giardia infections. The kappa index revealed that both coproparasitological techniques closely agreed on the Giardia diagnosis (86 percent) versus satisfactory (72 percent) and poor (35 percent) concordances for commensal protozoan and helminth infections, respectively. Concerning Giardia molecular diagnosis, from the 71 microscopy-positive samples, specific amplification of gdh and tpi fragments was noted in 68 (95.7 percent) and 64 (90 percent) samples, respectively. Amplification of gdh and tpi genes was observed, respectively, in 95.7 percent and 90 percent of microscopy-positive Giardia samples. For 144 microscopy-negative samples, gdh and tpi gene amplification products were obtained from 8.3 percent and 35.9 percent samples, respectively. The agreement between these genes was about 40 percent. The centrifuge-flotation based method was the most suitable means of Giardia diagnosis assessed in the present study by combining accuracy and low cost.(AU)

Zoonoses causadas por parasitas intestinais de cães e o problema do diagnóstico

ABSTRACT The last 20 years have witnessed a great technological progress along with important cultural and social changes that have improved some aspects of both human and animal health. However, zoonotic diseases caused by dog intestinal parasites persist as a commonplace public health concern in developing countries and as an increasing problem in developed ones. The effectiveness and security of the new drugs available for the prophylaxis and control of parasites has not hindered the emergence of parasitic infection as a serious problem in pets. This review aimed to examine some of the more important intestinal parasites of dogs involved in zoonotic diseases and to highlight issues associated with their diagnosis. The main purpose is to advise veterinarians in clinical practice concerning their importance as a public health agent in preventing and controlling dog zoonotic diseases through the correct use of antiparasite drugs and by educating pet owners.

RESUMO Os últimos 20 anos foram marcados por um intenso progresso tecnológico e por importantes alterações culturais e sociais com reflexos tanto em saúde humana como animal. Entretanto, infelizmente, as zoonoses causadas por parasitas intestinais de cães não deixaram de ser um problema permanente de saúde pública nos países em desenvolvimento, e uma preocupação crescente nos países desenvolvidos. A eficácia e segurança dos novos produtos disponíveis para a prevenção e controle não impediram que enfermidades parasitárias emergissem como um sério problema em animais de companhia. Nesta revisão, foram consideradas as principais espécies de parasitas intestinais de cães, responsáveis por zoonoses, e os aspectos relativos ao diagnóstico coproparasitológico com o objetivo de contribuir para um maior comprometimento dos médicos veterinários no importante papel de agentes promotores de saúde pública e de difusores do conhecimento.

Occurrence of Tetrameres confusa (Nematoda, Tetrameridae) in Ara ararauna (Psittacidae) / Ocorrência de Tetrameres confusa (Nematoda, Tetrameridae) em Ara ararauna (Psittacidae)

Relata-se a ocorrência de Tetrameres confusa Travassos 1917 (= T. americana (Cram, 1927) Baylis, 1929) (Nematoda, Tetrameridae) em um novo hospedeiro, Ara ararauna Linnaeus, 1758 (Aves, Psittacidae). Este é o primeiro registro da ocorrência do nematódeo em psitacídeos no Brasil.(AU)

Strongyloides venezuelensis infection susceptibility of seven inbred strains of mice / Susceptibilidade de sete linhagens isogênicas de camundongos à infecções por Strongyloides venezuelensis

A trial was carried out to investigate the susceptibility of seven strains of mice to Strongyloides venezuelensis primary and secondary experimental infections, in order to provide the basis for genetic studies about resistance. Twelve six-week-old male inbred mice of the A/J, BALB/c, CBA/J, C3H/Hepos, C57BL/6, DBA/2 and NIH strains were infected s.c. with 2000 infective larvae. The mean worm counts (± SD) in the small intestine six days after infection were, in increasing order: 28 (± 19) in NIH; 647 (± 228) in BALB/c; 709 (± 425) in DBA/2; 731 (± 151) in C3H/Hepos, 801 (± 174) in CBA/J; 1024 (± 267) in C57BL/6 and 1313 (± 483) in A/J. C57BL/6 mice showed the highest fecal egg counts and NIH, the lowest. No eggs in fecal exams or nematodes in small intestines were recovered from animals reinfected 14 days after primary infection. NIH strain was highly resistant to primary infection by S. venezuelensis. The most susceptible of the other six strains appeared to be the C57BL/6 strain which presented a high nematode counting in intestine and the highest egg output.(AU)

Foi investigada a susceptibilidade de sete linhagens isogênicas de camundongos à infecção experimental, primária e secundária, por Strongyloides venezuelensis a fim de servir de base para estudos genéticos sobre a resistência. Foram utilizados 12 camundongos machos, com seis semanas de idade, das seguintes linhagens isogênicas: A/J, BALB/c, CBA/J, C3H/Hepos, C57BL/6, DBA/2 e NIH. Os animais foram inoculados, via sub-cutânea, com 2000 larvas infectantes. As contagens médias (± desvio padrão) de parasitas no intestino delgado dos camundongos seis dias após a infecção, em ordem crescente, foram: 28 (± 19) na linhagem NIH; 647 (± 228) na BALB/c; 709 (± 425) na DBA/2; 731 (± 151) na C3H/Hepos, 801 (± 174) na CBA/J; 1024 (± 267) na C57BL/6 e 1313 (± 483) na A/J. Os camundongos C57BL/6 apresentaram as mais elevadas contagens de ovos de S. venezuelensis por grama de fezes (OPG) e os NIH, as mais baixas. Não foram detectados ovos nos exames de fezes e não foram encontrados parasitas no intestino delgado dos animais re-infectados 14 dias após a infecção primária. A linhagem NIH apresentou elevada resistência contra as infecções primárias por S. venezuelensis. Entre as outras seis linhagens, uma das mais susceptíveis foi a linhagem C57BL/6.(AU)

Parasitological characteristics and tissue response in the abomasum of sheep infected with Haemonchus spp.

A histopathological study was conducted on the abomasal mucosa of 40 Corriedale sheep exposed to natural infection with Haemonchus spp. The sheep were allowed to graze on contaminated pastures for 14 days and, after being housed for 28 days, they were slaughtered. Fecal samples were collected for fecal egg counts (FEC) and abomasum samples were obtained for histopathological examination and eosinophil, mast cell and globule leucocyte counts. The number of Haemonchus spp. present in the abomasum was estimated from a 10% aliquot of its content. The number of eggs per female was estimated for 10 Haemonchus spp. females collected from each animal. The following significant correlation coefficients were obtained between the characteristics analyzed: number of Haemonchus and FEC (r = 0.86), female length and number of eggs per female (r = 0.60), female length and FEC (r = 0.53), number of eosinophils and number of Haemonchus (r = 0.48), number of eosinophils and number of globule leucocytes (r = 0.54), number of mast cells and female length (r = -0.39), and number of mast cells and number of globule leucocyte (r = 0.34). The characteristics that showed the highest correlation with animal load was FEC.

Realizou-se um estudo histopatológico da mucosa do abomaso de 40 cordeiros da raça Corriedale, expostos à infecção natural por Haemonchus spp. Os cordeiros foram colocados em pastagens contaminadas por 14 dias e após 28 dias de estabulação foram necropsiados. Por ocasião da necropsia, foram colhidas amostras de fezes para a realização da contagem de ovos por grama de fezes (OPG) e amostras do abomaso para exame histopatológico e contagem do número de eosinófilos, mastócitos e leucócitos globulares. O número de Haemonchus spp. presente no abomaso foi estimado a partir de uma alíquota de 10% do conteúdo. O número de ovos por fêmea foi estimado em 10 fêmeas de Haemonchus spp. colhidas de cada animal. Coeficientes de correlação significativos entre as características analisadas foram: número de Haemonchus e contagem de OPG (r = 0,86); comprimento de fêmeas e número de ovos por fêmea (r = 0,60); comprimento de fêmeas e contagem de OPG (r = 0,53); número de eosinófilos e número de Haemonchus (r = 0,48); número de eosinófilos e número de leucócitos globulares (r = 0,54); número de mastócitos e comprimento de fêmeas (r = -0,39) e número de mastócitos e número de leucócitos globulares (r = 0,34). Das características analisadas a que apresentou maior correlação com a carga parasitária dos animais foi a contagem de OPG.