RESUMEN

The aim of this study was to evaluate the rapid tests currently used for canine parvovirus (CPV) diagnosis: hemagglutination test (HA), enzyme immunoassay (EIA) and polymerase chain reaction (PCR). A total of 112 fecal samples collected from diarrheic puppies up to one year of age were tested. The EIA was able to detect CPV antigen in 44 samples. By HA, 32 samples tested highly positive with titers >128, eight tested weakly positive (titers 32 and 64) and 72 were negative (titers <16). Using PCR, 57 samples were found positive including 13 EIA-negative and 19 HA-negative samples. The best correlation was observed between EIA and PCR (88.4%). These tests were able to detect all types of CPV, including CPV-2c. Considering that 23%-33% of dogs presenting enteritis did not show infection by EIA nor HA, negative results from the antigen detection tests should be confirmed through molecular methods.

Avaliaram-se os métodos rápidos rotineiramente utilizados para diagnóstico da infecção por parvovírus canino (CPV): teste de hemaglutinação (HA), ensaio imunoenzimático (EIE) e reação em cadeia pela polimerase (PCR). Um total de 112 amostras fecais de cães diarreicos com até um ano de idade foi testado. O EIE foi capaz de detectar o antígeno do CPV em 44 amostras. Por HA, 32 amostras foram consideradas fortemente positivas com títulos >128, oito fracamente positivas (títulos 32 e 64) e 72 negativas (títulos <16). Por PCR, 57 amostras foram positivas incluindo 13 EIE-negativas e 19 HA-negativas. A melhor correlação foi observada entre EIE e PCR (88,4%). Os testes foram capazes de detectar todos os tipos de CPV, incluindo o CPV-2c. Considerando-se que em 23%-33% dos filhotes com enterite a infecção por CPV não foi diagnosticada pelos testes de EIE e HA, os resultados negativos nos testes de detecção de antígeno devem ser confirmados por meio de métodos moleculares.

Asunto(s)

RESUMEN

The objective of this study was to investigate, by partial sequencing of VP2 protein, the variability of CPV detected in 37 fecal samples collected from vaccinated puppies with enteritis. Laboratorial diagnosis of CPV was confirmed by HA/HI and PCR and, for sequencing analyses, two different regions of the VP2 gene were amplified by PCR. From 1995 to 2004, all strains were characterized as CPV-2a. After that, both CPV-2a and CPV-2b were detected. All CPV-2a showed a non-synonymous mutation in the residue 297 (Ser→Ala). A synonymous substitution at the AA 574 was also observed in 15/37 samples. Our findings indicate that the cases of vaccine failure are most likely not associated to the mutations detected in the sequenced regions. However, the monitoring of genotyping mutations that led to new CPV strains is essential to determinate if current vaccines will keep providing protection against all new future variants.

Asunto(s)

RESUMEN

Canine parvovirus (CPV) is the most important enteric virus for dogs and it seems to be undergoing continuous evolution, generating new genetic and antigenic variants throughout the world. The aim of this study was to analyze the distribution of CPV variants from 1995 to 2009 and to investigate the circulation of the new variant CPV-2c in Rio de Janeiro, Brazil. In addition, the clinical features of CPV infection were also reported. After CPV laboratorial confirmation by HA/HI and PCR, thirty-two fecal samples were analyzed by sequencing a 583-bp fragment of the VP2 gene. One sample, collected in 2008 was typed as the new type CPV-2c. All samples from 1995 to 2003 were identified as "new CPV-2a". From 2004 to 2006, both "new CPV-2a" and CPV-2b were observed. From 2006 to 2009, most of the samples were characterized as CPV-2b. The classical signs of CPV enteritis were observed in 16/18 CPV-2a and 5/13 CPV-2b infected puppies. These results show that continuous epidemiological surveillance of CPV strain distribution is essential for studying the patterns of CPV-2a and 2b spread and for determining whether the new variant CPV-2c has become permanently established in Brazilian canine population.

RESUMEN

Canine parvovirus (CPV) is the most important enteric virus for dogs and it seems to be undergoing continuous evolution, generating new genetic and antigenic variants throughout the world. The aim of this study was to analyze the distribution of CPV variants from 1995 to 2009 and to investigate the circulation of the new variant CPV-2c in Rio de Janeiro, Brazil. In addition, the clinical features of CPV infection were also reported. After CPV laboratorial confirmation by HA/HI and PCR, thirty-two fecal samples were analyzed by sequencing a 583-bp fragment of the VP2 gene. One sample, collected in 2008 was typed as the new type CPV-2c. All samples from 1995 to 2003 were identified as "new CPV-2a". From 2004 to 2006, both "new CPV-2a" and CPV-2b were observed. From 2006 to 2009, most of the samples were characterized as CPV-2b. The classical signs of CPV enteritis were observed in 16/18 CPV-2a and 5/13 CPV-2b infected puppies. These results show that continuous epidemiological surveillance of CPV strain distribution is essential for studying the patterns of CPV-2a and 2b spread and for determining whether the new variant CPV-2c has become permanently established in Brazilian canine population.

RESUMEN

This paper relates the clinical and epidemiological aspects of canine parvovirus infection (CPV) in the State of Rio de Janeiro from April 1995 to March 2004. A total of 341 fecal samples were collected from up to 6-months-old puppies with gastroenteritis. The diagnosis of CPV infection was confirmed by hemagglutination/ hemagglutination inhibition tests, enzyme immunoassay, virus isolation in cell culture or polymerase chain reaction. One hundred and fifty-seven samples (46 percent) were positive for CPV. No correlation among sex, breed or age and the occurrence of CPV infection was observed. The classical signs of parvoviral enteritis (anorexia, lethargy, vomiting and hemorrhagic fluid diarrhea) were observed in 70 percent of CPV-positive and in 60 percent of CPV-negative puppies. Although CPV could be detected throughout the studied period, its occurrence was significantly higher from June to September and November to December. These results show that CPV is still circulating in the State of Rio de Janeiro.

Este trabalho relata os aspectos clínicos e epidemiológicos da infecção pelo CPV no Estado do Rio de Janeiro, no período de abril de 1995 a março de 2004. Coletaram-se 341 amostras fecais de cães com até seis meses de idade que apresentavam gastrenterite. O diagnóstico da infecção pelo CPV foi confirmado através dos testes de hemaglutinação/inibição da hemaglutinação, ensaio imunoenzimático, isolamento viral em cultura de células ou reação em cadeia pela polimerase. Cento e cinqüenta e sete amostras (46 por cento) foram consideradas positivas para CPV. Não foi observada correlação entre sexo, raça ou idade e a ocorrência da infecção por CPV. Os sinais clínicos clássicos de parvovirose (vômito, anorexia, apatia e diarréia líquida hemorrágica) foram observados em 70 por cento dos animais positivos e 60 por cento dos animais negativos para CPV. O CPV foi detectado ao longo do período estudado, entretanto observou-se um aumento do número de casos positivos nos períodos de junho a setembro e novembro a dezembro. Estes resultados mostram que o CPV ainda circula no Estado do Rio de Janeiro.

Asunto(s)

RESUMEN

In this study, the genomic types of canine parvovirus (CPV) circulating in the State of Rio de Janeiro, Brazil, from 1995 to 2001, were investigated using the polymerase chain reaction assay (PCR). A total of 78 faecal samples from gastroenteritic puppies, confirmed as positive for canine parvovirus by haemagglutination/haemagglutination inhibition tests or virus isolation in cell culture (MDCK), were examined. The viral DNA was extracted from faecal samples using a combination of phenol- chloroform and silica-guanidine thiocyanate methods. PCR was carried out with differential pairs of primers to distinguish the old (CPV-2) and new types of virus (CPv-2a or CPV-2b). Specific amplicons were observed for all samples using the primer pair P2ab, which detects CPV-2a and CPV-2b. Seventy-six from a total of 78 samples (97%) were considered as CPV-2b because of their reaction with the primer pair P2b. Thirty samples (30/78) were from previously vaccinated puppies and in 15 of them the enteritis symptoms began from 1 to 12 days after vaccination. PCR confirmed the infection by wild virus (CPV-2b) in 5 of these 15 puppies who had received old-type vaccines. Our results show that CPV-2b was the prevalent type circulating in the State of Rio de Janeiro from 1995 to 2001.

Asunto(s)

RESUMEN

Colheram-se 163 amostras fecais no período de 1995 a 2001 para investigar a ocorrência da infecção por parvovírus e rotavírus em cães com gastrenterite utilizando-se a técnica de eletroforese em gel de poliacrilamida. Em três amostras observou-se a presença do genoma bisegmentado similar ao perfil eletroforético dos picobirnavírus (PBV) e em uma, três segmentos de RNA dupla fita, característico de picotrirnavírus. Das amostras positivas para PBV, duas foram obtidas de filhotes e uma foi positiva para parvovírus canino. Este é o primeiro relato da detecção de vírus com genoma bisegmentado em cães com diarréia no Estado do Rio de Janeiro.

Asunto(s)

RESUMEN

Kidneys of 16 beagles with experimentally induced heartworm (Dirofilaria immitis) infections and 4 heartworm-nai;ve dogs were studied by light and electron microscopy. The infections were induced either by subcutaneous injection of infective larvae or by the transplantation of adult parasites, and infection periods varied from 111 to 818 days and 365 to 923 days, respectively. One control group of heartworm-naïve dogs and four groups of heartworm-infected dogs, which were divided according to the type and the length of infection, were used. In the infected dogs, thickening of the glomerular basement membrane (GBM), the presence of dense deposits in the GBM, and foot process effacement were the most frequent lesions observed. In some dogs, electron dense deposits were seen in the GBM and the mesangium and/or enlargement of the mesangial matrix could be characterized. The longer the infection period, the thicker the GBM and the more common the occurrence of foot process effacement. In general, these alterations were more evident in animals that had been infected for more than 1 year, had high microfilaremia, and had 14 or more parasites in the main pulmonary artery and its branches. The presence of dense deposits suggests that the pathogenesis of kidney disease in dirofilariasis is associated with deposits of immune complexes in the membrane. The finding of ultrastructural changes in dogs with early prepatent infections suggests that immature heartworms, as well as microfilariae and possibly adult worms, contribute to the glomerulonephropathy.

Asunto(s)

RESUMEN

Dirofilaria immitis (Leidy 1856), a nematode parasite, is the etiologic agent of canine heartworm disease and mosquitoes are essential intermediate hosts. Mosquito susceptibility to the worms differ with species, strains and also among individuals of the same strain. To evaluate the degree of susceptibility of Rio de Janeiro laboratory raised strain of Aedes aegypti, we fed mosquitoes on canine blood with different densities of microfilariae (mf). There was no significant difference in the rate of development among the three different densities of mf. Infective larvae were found in the head and proboscis of all mosquitoes provided bloodmeals with different densities of mf after the 11th day post-infection. The infection rate of mosquitoes after ingestion of blood containing 3,000 mf/ml, 5,000 mf/ml and 7,000 mf/ml were 55.3%, 66.7% and 100%, respectively. The vector efficiency indices ranged from 1.6 to 9.3. The finding of L3 stage larvae, high infection rates and vector efficiency indices suggest that Ae. aegypti, Rio de Janeiro laboratory strain, is a potential vector of D. immitis, although of low efficiency.

Asunto(s)

RESUMEN

The identification of arthropod bloodmeals is important in many epidemiological studies, as, the understanding of the life cycle of vectors and the pathogens they transmit, as well as helping to define arthropods' control strategies. The precipitin test has been used for decades, but ELISA is slowly becoming more popular. To compare the two tests for sensitivity, specificity and accuracy to detect small insect bloodmeals, Aedes aegypti or Ae. fluviatilis mosquitoes were fed either on feline, canine or human hosts. Mosquitoes were frozen at 6, 12, 24, 48 or 72 h after feeding. Precipitin test showed better specificity and accuracy and ELISA test showed higher sensitivity. Better results with both tests were achieved when mosquitoes were frozen within 48 h from feeding.

Asunto(s)

RESUMEN

Six hundred and eleven random-source dogs (338 male, 273 female) one year of age or older, from six sections of the city of Recife, Pernambuco, were examined antemortem for circulating microfilariae Dirofilaria immitis and Dipetalonema reconditum adult heartworm (D. immitis) antigen, and examined postmortem for adult heartworms. The prevalence of heartworm infection was 2.3% (14/611), as determined by necropsy for adult worms, and 1% (6/611) had circulating microfilariae of D. immitis; thus, 57.1% of the heartworm-infected dogs had occult infections. The results of serological testing indicated that 1.3% (8/611) of the dogs were positive for adult heartworm antigen. A total of 42 (6.9%) of the dogs had microfilariae of D. reconditum; 40 of these had only D. reconditum and two additional dogs had microfilariae of both species, D. immitis and D. reconditum.

Asunto(s)

RESUMEN

Dirofilaria immitis is a widespread mosquito-borne parasite that causes dirofilariasis, a commonly diagnosed disease of dogs that is rarely reported in cats and humans. A mosquito survey was conducted in Itacoatiara in the State of Rio de Janeiro, from March 1995 to February 1996, using canine, feline and human baits. A total of 3,667 mosquitoes were dissected for D. immitis larvae, representing 19 species and 10 genera. From those, Ae. scapularis, Ae taeniorhynchus, Cx. quinquefasciatus, Cx. declarator, Cx. saltanensis and Wy. bourrouli were found infected with D. immitis parasites, and among those only the first three harbored infective larvae. The majority of larvae were found in the Malpighian tubules (889/936), and larval melanization was observed in the two Aedes species. In descending order, the best vectors were Ae. scapularis. Ae. taeniorhynchus, and Cx. quinquefasciatus which alternate seasonally in importance. Cx. quinquefasciatus is suggested to be a vector to cats. The potential transmission of D. immitis parasites by these three vectors to man is discussed.

Asunto(s)

Asunto(s)

RESUMEN

Heartworm, a chronic fatal mosquito-borne canine disease, is frequently diagnosed in dogs from the State of Rio de Janeiro, where its prevalence is 29.7% in the city of Niterói. Nevertheless it is rarely detected in cats (0.8%) from the same state. Dogs are the primary source of infection to mosquitoes. because cats either do not demonstrate microfilaremia or it is too low and transient for transmission. A mosquito survey was conducted in Itacoatiara, Niterói, from March 1995 to February 1996, using canine, feline and human baits. A total of 21 mosquito species (3,888 females) was collected and biting frequency was higher at dusk. The four species collected most frequently (88.9%) were: Aedes taeniorhynchus (30% of the total catch; with the peak in May/June); Culex quinquefasciatus (22.5%; August/October); Aedes scapularis (19.4%; August, October/November and January) and Culex declarator (17%; November/January). Human baits were attractive to these species and dogs were significantly more attractive to them than cats. Ae. taeniorhynchus, Cx. quinquefasciatus, Ae. scapularis, Cx. declarator and Cx. nigripalpus are the most likely mosquito species to transmit Dirofilaria immitis parasites to dogs and may transit the parasite to humans. It is also suggested that the vector to cats belongs to the games Culex.

Asunto(s)

RESUMEN

To evaluate the prevalence of heartworm disease in metropolitan Rio de Janeiro, RJ, Brazil, cats submitted for euthanasia were evaluated by laboratory tests and by necropsy for signs of heartworm infection. Of the 135 cats examined, one (0.8%)--a stray male from an urbanizing district--had one male worm (14.5 cm) in the left lung and showed severe muscular hypertrophy of small pulmonary arteries and arterioles with no right ventricle enlargement or passive congestion. Microfilariae were not detected in the blood of any cats. The prevalence of canine heartworm in the area from which this cat originated is estimated to be approximately 12%. The prevalence of canine heartworm in the urban area of Rio de Janeiro has been determined to be approximately 5%. It has been shown that the prevalence of feline heartworm disease parallels that in dogs, but at a lower rate. Results of this survey strongly suggest that heartworm prevention measures should be taken under consideration, especially among cats living in a high canine heartworm prevalence area.

Asunto(s)

RESUMEN

In order to evaluate the prevalence of canine heartworm in the State of Rio de Janeiro, a multicenter survey was carried out in two phases. The survey involved 1376 dogs from two cities: Rio de Janeiro and Niterói, and its surroundings, including the eastern shore and mountain resorts, which were further divided into sections. In the first phase, 795 dog blood samples were examined by the modified Knott test for the detection of microfilariae. A total of 134 samples (16.85%) were microfilaremic: 8.61% from Rio de Janeiro, 21.76% from Niterói and its surroundings, 33.33% from the eastern shore and 30.43% from the mountain resorts. In the second phase, 595 dog blood samples were examined first by the modified Knott test and the amicrofilaremic samples were subsequently examined by an immunoenzymatic test (ELISA) for antigen detection. In summary, 83 samples (13.95%) were microfilaremic and 44 (7.98%) of the amicrofilaremic samples were positive for heartworm antigen (occult infections). In Rio de Janeiro, 13.68% of the dogs were infected (i.e., antigen- and/or microfilaria-positive) and 8.51% of the dogs had microfilaremic infections. In comparison, Niterói and its surroundings showed values of 24.46% and 17.30% and the eastern shore showed values of 52.46% and 31.15%. In contrast the mountain resorts showed 20% microfilaremic only.

Asunto(s)

RESUMEN

This study is concerned with aspects of the relationship between ticks and their hosts that have a bearing on biological control of tick populations. It proposes control methods based on a program that would combine development of an effective vaccine with genetic selection of hosts.

RESUMEN

Calves were immunized with Boophilus microplus saliva, filtered through Millipore membranes, in Freund's complete adjuvant. Serum samples were tested by passive hemagglutination against Babesia bigemina, Anaplasma marginale, B. microplus larvae extract, Stomoxys calcitrans extract and B. microplus saliva. After immunization, titers to saliva, larval tick-extract and to S. calcitrans were increased. The challenge with live tick larvae enhanced the formation of antibodies against larva extract, fly extract and tick saliva, which supports the idea that under natural controlled conditions this cross-reactivity could occur.

Asunto(s)

RESUMEN

Estudos imunologicos foram realizados em 16 pacientes adultos, de ambos os sexos, acometidos de paracoccidioidomicose. Dentre os achados mais importantes figuram os teores elevados de IgG, a baixa do 3o. componente do complemento, a presenca de anticorpos precipitantes e hemaglutinantes contra a paracoccidioidina, a presenca de complexos imunes circulantes, baixos teores de linfocitos T circulantes, teores normais de linfocitos T supressores e hiporreatividade dos linfocitos T a fitohemaglutinina e a paracoccidioidina.A histologia das reacoes cutaneas a paracoccidioidina acusou um aspecto semelhante ao da reacao de Arthus, com o maximo de intensidade do eritema em 24 horas, a presenca de vasculite e a infiltracao predominante por polimorfonucleares

Asunto(s)