Immune response in cattle vaccinated against rabies

In order to determine the best type of rabies vaccine to use as a booster, 78 serological samples from singly vaccinated cattle were analyzed by counterimmunoelectrophoresis technique. The animals were divided into several groups, received the first vaccine dose with modified live virus vaccine (ERA strain) and were revaccinated with inactivated virus or modified live virus vaccines. Boosters were given at 2, 4, 8, 12 and 16 weeks following first vaccination. Results showed high titres in the cases of booster with inactivated vaccine. In all cases, however, detectable antibody titres declined quickly.

Detection of poxvirus in cattle associated with human cases in the State of Rio de Janeiro: preliminary report

This preliminary report describes human and cow cases of poxvirus that recently ocurred in the State of Rio de Janeiro. The electron microscopic findings were consistent with parapoxviral and orthopoxviral infection. Orthopoxvirus strains were isolated from human and cow cases. Detailed viral characterization by means of genetical techniques is under investigation. Based on these informations, poxviral diseases should be also considered an emerging viral zoonosis that can affect human beings.

Description of males of Parabronema pecariae Ivaschkin, 1960 (Nematoda, Habronematoidea) parasitizing peccaries (Mammalia, Tayassuidae) in Brazil

Nematodes studied herein and identified as Parabronema pecariae were collected in 1936 in the States of Rio de Janeiro and Pará and in 1940 in the State of Mato Grosso do Sul, Brazil. This species was proposed, with basis on female specimens that had been described earlier as Parabronema sp. Although the presence of males of P. pecariae was previously reported in Brazil, their description was not provided. The present paper deals with the first complete morphometric data on male specimens of P. pecariae recovered from peccaries (Pecari tajacu and Tayassu pecari).

Worm burdens in outbred and inbred laboratory rats with morphometric data on Syphacia muris (Yamaguti, 1935) Yamaguti, 1941 (Nematoda, Oxyuroidea)

Syphacia muris worm burdens were evaluated in the rat Rattus norvegicus of the strains Wistar (outbred), Low/M and AM/2/Torr (inbred), maintained conventionally in institutional animal houses in Brazil. Morphometrics and illustration data for S. muris recovered from Brazilian laboratory rats are provided for the first time since its proposition in 1935.

Development of an enzyme-linked immunosorbent assay for detection of IgM antibodies to Babesia bigemina in cattle

A crude antigenic preparation of Babesia bigemina was used to develop an ELISA for the detection of IgM antibodies. Optimal dilutions of the antigen, using positive and negative reference sera, were determined by checkerboard titrations. Negative sera from cattle imported from tick-free areas, serum samples collected from infected B. bigemina cattle were used to validate the test. The specificity was 94% and sensitivity of the Elisa 87.5%. Sera from 385 cattle deriving from areas free from tick-borne diseases, which were submitted to a preimmunization process, were screened by this technique. The Elisa detected seroconversion on the 14th day post-inoculation in animals either infested with Boophilus microplus ticks (infected with B. bigemina), or inoculated with B. bigemina infected blood. Antibody titers decreased after day 33; however, all animals remained positive until the end of the experiment (124 days). The ELISA described may prove to be an appropriate serological test for the detection of IgM antibodies against B. bigemina.

New host and locality records for Tetrameres (Gynaecophila) spirospiculum Pinto & Vicente, 1995 (Nematoda: Tetrameridae), with new morphological data

We report the finding of Tetrameres spirospiculum Pinto & Vicente, 1995 from Theristicus melanopis melanopis (Threskiornithidae) from Patagonia, Argentina. These constitute new host and locality records. We propose the assignation of this species to the subgenus T. (Gynaecophila) Gubanov, 1950, based on the presence of labia and the absence of cuticular flanges at the anterior end. Some new morphological data are provided, such as the arrangement of cuticular spines and the presence of a pair of somatic papillae at beginning of posterior third of body length. T. (G.) spirospiculum may probably be regarded as specific to birds of the genus Theristicus.

Dynamics of Haematobia irritans irritans (Diptera: Muscidae) infestation on Nelore cattle in the Pantanal, Brazil

From June 1993 to May 1995, horn fly counts were conducted twice a month on untreated Nelore cattle raised extensively in the Pantanal. Horn fly population showed a bimodal fluctuation and peaks were observed every year after the beginning (November/December) and at the end (May/June) of the rainy season, which coincided with mid-late spring and mid-late fall, respectively. Horn flies were present on cattle throughout the year in at least 64% of the animals. Mean horn fly numbers on animals did not exceed 85 flies/cow during peaks and were under 35 flies/cow in most of the remaining periods. The highest infestations (population peaks) were short and dropped suddenly within two weeks. Less than 15% of the animals in both herds could be considered as "fly-susceptible" - showing consistently higher infestations, or "fly-resistant" - showing consistently lower infestations.

Simuliid blackflies (Diptera: Simuliidae) and ceratopogonid midges (Diptera: Ceratopogonidae) as vectors of Mansonella ozzardi (Nematoda: Onchocercidae) in northern Argentina

Mansonella ozzardi, a relatively non pathogenic filarial parasite of man in Latin America, is transmitted by either ceratopogonid midges or simuliid blackflies. In the only known focus of the disease in north-western Argentina the vectors have never been incriminated. This study investigated the potential vectors of M. ozzardi in this area. The only anthropophilic species of these Diptera families biting man at the time of the investigation were Simulium exiguum, S. dinellii, Culicoides lahillei and C. paraensis. Using experimentally infected flies S. exiguum and both species of Culicoides allowed full development of microfilariae to the infective stage, with C. lahillei being a more competent host than S. exiguum. Based on these data, biting rates and natural infectivity rates it is probable that at the begininning of the wet season C. lahillei is the main vector of M. ozzardi and both C. paraensis and S. exiguum secondary vectors. Additionally, it was found that a single dose of ivermectin was ineffectual in eradicating M. ozzardi from infected individuals in this area.

Human infection by Pseudoterranova decipiens (Nematoda, Anisakidae) in Chile: report of seven cases

From 1997 to 1999, we identified seven human cases of infection by fourth stage larvae of Pseudoterranova decipiens in Chile. All identified larvae were coughed up by the patients. Subjects were 10-55 years old; five were female. Some patients complained of coughing, expectoration, pharyngeal pain, nausea or anal and nasal pruritus. Larvae of three patients were coughed up from 36 h to 7 days after having eaten raw (cebiche or sushi) or lightly fried fish. P. decipiens has a marine life cycle. Infective third stage larva develop to adult stage in pinniped mammals. The nematode eggs are voided with the host faeces and develop and hatch releasing third stage larvae. Some crustaceans and fish act as hosts of third stage larvae. Man is an accidental host for third or fourth stage larvae.

Cattle Dung Breeding Diptera in Pastures in Southeastern Brazil: Diversity, Abundance and Seasonallity

Diptera that breed in undisturbed cattle droppings in pastures present great diversity and abundance, and several species are of veterinary importance and may cause economic losses. To survey the diversity, abundance and seasonality of Diptera associated to this microhabitat, 83 samples of 10 dung pats each were taken from April 1992 to April 1994 in the vicinity of São Carlos, State of São Paulo, Southeastern Brazil. A total of 46,135 Diptera belonging to 20 families and at least 51 species were found to breed in the pats. The most abundant and diverse families were Sepsidae, Muscidae, Sarcophagidae and Sphaeroceridae. In general, the abundance was higher from October to March, the warm and wet months. The importance of some Diptera, both as horn fly enemies and as cattle dung decaying agents, is discussed.

Some Morphological Aspects of Cylicocyclus brevicapsulatus (Nematoda: Cyathostominae) Parasite of Horse

This paper describes some morphological aspects of Cylicocyclus brevicapsulatus (Ihle, 1920) (Nematoda: Cyathostominae) from Equus caballus in Brazil. The worms were studied using an optical microscope (measurements and illustrations) and a scanning electron microscope for a more detailed examination of the external morphology. The buccal capsule is very short, with a very thin wall, and the dorsal gutter is absent. Other morphological aspects are described including measurement of the spicules and gubernaculum.

First Report of Lappetascaris lutjani Rasheed, 1965 (Nematoda, Ascaridoidea, Anisakidae) Parasitizing Trachipterus arawatae (Pisces, Lampridiformes) on the Atlantic Coast of Brazil

New host and geographical records are reported for the nematode Lappetascaris lutjani Rasheed, 1965, parasitizing the marine fish Trachipterus arawatae Clark, 1881 in Brazilian waters. Morphometric data and illustrations of the parasites are included.

Stenurus globicephalae Baylis et Daubney, 1925 (Nematoda: Pseudaliidae) from a False Killer Whale, Pseudorca crassidens (Cetacea: Delphinidae), Stranded on the Coast of Uruguay

Stenurus globicephalae Baylis et Daubney, 1925 (Nematoda: Pseudaliidae) was found in the cranial air sinuses of a false killer whale, Pseudorca crassidens (Owen), stranded on the coast of Uruguay in 1999. Although this species has been reported once in P. crassidens from the North Atlantic, this is the first record for South America. A total of 920 specimens were obtained, of which 663 were females (body length: 4.34 ± 0.45 cm) and 257 were males (2.99 ± 0.18 cm). Morphometric details are presented for S. globicephalae in this host, which do not show significant differences from those parasitizing Globicephala melas (Traill), but are distinct from those parasitizing Peponocephala electra (Gray). The host's skull revealed loss of osseous mass with the disappearance of the left zygomatic arch, and the left jaw had three osseous fenestrations in the region related to the organ of acoustic reception. These lesions support the hypothesis that this infection, known as stenurosis, was related to the stranding.

Effect of the Contents and Form of Rabies Glycoprotein on the Potency of Rabies Vaccination in Cattle

One of the methods used for controlling cattle rabies in Brazil consists of vaccination. Sometimes, however, rabies occurs in cattle supposedly protected. Since rabies vaccine batches are officially controlled by tests performed on laboratory animals, it is questionable whether the minimal mandatory requirements really correspond to immunogenicity in the target species. We have analyzed the association among potencies of rabies vaccines tested by the NIH test, the contents and form (free-soluble or virus-attached) of rabies glycoprotein (G) in the vaccine batches, and the virus-neutralizing antibodies (VNA) titers elicited in cattle. No correlation was found between G contents in the vaccine batches and the NIH values, whatever the presentation of G. There was no correlation either between NIH values and VNA titers elicited in cattle. There was, however, a positive correlation (r = 0.8681; p = 0.0001) between the amounts of virion-attached G present in the vaccine batches and VNA elicited in cattle. This was not observed when the same analysis was performed with total-glycoprotein or free-soluble glycoprotein. The study demonstrated that NIH values can not predict the effect of the immunogen in cattle. On the other hand, the quantification of virus-attached rabies glycoprotein has a strong correlation with VNA elicited in cattle.