Serological and bacteriological responses of water buffalo (Bubalus bubalis) vaccinated with two doses of Brucella abortus strain RB51 vaccine.

Thirty-two water buffalo (Bubalus bubalis) calves aged 6­10 months were used to evaluate serological responses to Brucella abortus strain RB51 (RB51) vaccination in a dose-response study and to compare the use of two selective media for the isolation of RB51. The animals were randomly divided into three treatment groups. Groups I-III received the recommended vaccine dose (RD) twice 4 weeks apart, RD twice 18 weeks apart and saline once, respectively. Lymph nodes were excised from the three groups and subjected to bacteriological examination to determine the frequency of detection of RB51. Pre- and post-vaccination blood samples were collected and tested for B. abortus antibodies using the buffered plate agglutination test (BPAT), complement fixation test (CFT), and dot-blot assay. Sera taken at all post-inoculation weeks (PIW) were negative for field strain B. abortus using the BPAT. Antibody responses to RB51 were demonstrated in all vaccinates but not in controls by CFT and dot-blot assay from 1 PIW up to 16 weeks following booster vaccination. The agreement for both assays was 80.7% and there was a linear interdependence with a Pearson's correlation coefficient value of 0.578. The frequency of isolation of RB51 from the two selective media used was not significantly different (P > 0.05).

Frequency of detection of immunoglobulins of Toxoplasma gondii, Leptospira spp., and Brucella abortus in livestock/farm and abattoir workers in Trinidad.

Toxoplasma gondi, Leptospira spp., and Brucella abortus are all established parasitic and bacterial zoonoses that manifest themselves in several forms of human diseases. They have been associated with occupational exposures, particularly amongst workers associated with livestock farms. The primary objectives of this study were to determine the seroprevalence of T. gondii immunoglobulin M (IgM) immunoglobulins (serum antibodies), Leptospira IgM immunoglobulins, and B. abortus IgG immunoglobulins, suggestive of acute or chronic infections, in livestock/farm and abattoir workers in Trinidad, and to relate to risk factors. Blood samples were collected from 394 consenting livestock/farm workers and 99 abattoir workers across the island of Trinidad. Serological status was determined by enzyme immunoassay (EIA) for T. gondii IgM, enzyme-linked immunosorbent assay (ELISA) for Leptospira IgM immunoglobulins, and buffered plate agglutination test (BPAT) and competitive ELISA for B. abortus IgG immunoglobulins. Of 394 apparently healthy livestock/farm workers sampled, 150 (38.1%) were seropositive for T. gondii IgM immunoglobulins, compared with 44 (44.4%) of 99 abattoir workers (p > .05; χ(2) test). Five (1.3%) of 371 and 1 (1.0%) of 99 livestock/farm and abattoir workers respectively were positive for Leptospira IgM immunoglobulins. All samples from livestock/farm workers and abattoir workers were negative for B. abortus immunoglobulins. None of the risk factors investigated was statistically significantly (p > .05; χ(2) test) associated with T. gondii and Leptospira spp. infections.

Seroepidemiology of leptospirosis in livestock in Trinidad.

A study was conducted to determine the seroprevalence of leptospirosis and infecting serovars across livestock (cattle, sheep, goats, and pigs) in Trinidad using the microscopic agglutination test with an international panel of 23 serovars. Of a total of 590 cattle tested, 21.5% were seropositive with agglutinations to 13 of the 23 antigens used in the panel. Icterohaemorrhagiae (9.3%), Sejroe (4.1%), Ballum (4.1%), and Autumnalis (1.9%) were the predominant serogroups detected in the cattle sampled (n = 590). Of 222 sheep tested, 5.0% were seropositive with agglutinations to five serovars belonging to two serogroups. These serogroups were Autumnalis at 2.7%, and Icterohaemorrhagiae at 2.3% of all sheep tested (n = 222). Of a total of 180 goats tested, 3.3% were seropositive, all agglutinating to the Icterohaemorrhagiae serogroup, 1.7% to serovar Copenhageni, 1.1% to serovar Mankarso, and 0.6% to serovar Icterohaemorrhagiae. Among pigs (n = 200), 5.0% were seropositive for five serovars belonging to three serogroups. These serogroups were Icterohaemorrhagiae at 2.5%, Australis at 2%, and Ballum at 0.5%. Overall, age and sex of animals were not significantly associated with leptospirosis with the exception of cattle where age was a significant factor for seropositivity. It was concluded that for livestock, leptospirosis may be an important zoonotic and economic disease, particularly in the case of cattle. It is imperative that the impact of leptospirosis on abortion, stillbirths, and decreased milk production in livestock in the country be assessed.

A case of transplacental transmission of Theileria equi in a foal in Trinidad.

Equine piroplasmosis due to Theileria equi and Babesia caballi is endemic in Trinidad. A case of equine piroplasmosis due to T. equi was diagnosed in a thoroughbred foal at 10h post-partum. A high parasitaemia (63%) of piroplasms was observed in a Wright-Giemsa(®) stained thin blood smear from the foal. In addition, the 18S rRNA gene for Babesia/Theileria was amplified from DNA extracted from the blood of the foal and the mare. Amplified products were subjected to a reverse line blot hybridization assay (RLB), which confirmed the presence of T. equi DNA in the foal. The mare was negative by RLB but was positive for T. equi using a nested PCR and sequence analysis. In areas where equine piroplasmosis is endemic, severe jaundice in a post-partum foal may be easily misdiagnosed as neonatal isoerythrolysis. Foals with post-partum jaundice should be screened for equine piroplasmosis, which may be confirmed using molecular methods if available.

Comparative study on responses of cattle and water buffalo (Bubalus bubalis) to experimental inoculation of Brucella abortus biovar 1 by the intraconjunctival route--a preliminary report

The preliminary study was conducted to assess the virulence of a strain of Brucella abortus (1969D) and to compare the susceptibility of water buffalo and cattle calves to infection by the intraconjunctival route. Seven of each cattle and water buffalo (Bubalus bubalis) calves aged 3-6 months were inoculated intraconjunctivally with counts ranging from 1.5 ž 10(7) to 1.7 ž 10(10) colony forming units of B. abortus. Animals were monitored over an 8-week period for clinical manifestations and serological and hematological evidence of infection. At slaughter, eight lymph nodes from each animal were sampled for bacteriological and histopathological assessments. Lymph nodes from three water buffalo (43%) and five cattle (71%) yielded B. abortus (P=0.048). Parotid/prescapular lymph nodes were most sensitive in detecting B. abortus. Our data suggest that B. abortus strain 1969D may be used as challenge strain, and water buffalo appeared to have a lower susceptibility to B. abortus infection than cattle.

Comparative study on responses of cattle and water buffalo (Bubalus bubalis) to experimental inoculation of Brucella abortus biovar 1 by the intraconjunctival route--a preliminary report.

The preliminary study was conducted to assess the virulence of a strain of Brucella abortus (1969D) and to compare the susceptibility of water buffalo and cattle calves to infection by the intraconjunctival route. Seven of each cattle and water buffalo (Bubalus bubalis) calves aged 3-6 months were inoculated intraconjunctivally with counts ranging from 1.5 × 10(7) to 1.7 × 10(10) colony forming units of B. abortus. Animals were monitored over an 8-week period for clinical manifestations and serological and hematological evidence of infection. At slaughter, eight lymph nodes from each animal were sampled for bacteriological and histopathological assessments. Lymph nodes from three water buffalo (43%) and five cattle (71%) yielded B. abortus (P=0.048). Parotid/prescapular lymph nodes were most sensitive in detecting B. abortus. Our data suggest that B. abortus strain 1969D may be used as challenge strain, and water buffalo appeared to have a lower susceptibility to B. abortus infection than cattle.

Nucleic acid distribution pattern as a possible biomarker for metabolic activities of neoplastic cells: a digitally-aided fluorescence microscopy study on normal and neoplastic lymphocytes of acute and chronic canine lymphocytic leukemia.

BACKGROUND: Metabolic states of neoplastic cells are increasingly being relied upon for diagnostic and prognostic assessment of neoplastic conditions. The nucleic acid distribution pattern of cells in general, in terms of degree of condensation of the nuclear chromatin and overall spread of the nucleic acid within the nuclear and cytoplasmic compartments, can reflect the metabolic state of the cell. This simple but logical concept appears not be put into consideration to date as numerous attempts are being made towards formulating reliable biomarkers for rapid diagnosis, prognosis and subsequent therapeutic interventions for neoplastic conditions. We comparatively evaluated nucleic acid distribution patterns of normal lymphocytes and neoplastic cells of lymphocytic lineage, employing light and fluorescence microscopy procedures, as well as digital imaging analytical methods. RESULTS: The results demonstrate distinctiveness in the pattern of nucleic acid distribution for the normal lymphocytes and three lymphocytic neoplastic cell-types of canine lymphocytic leukemia that are categorized as small, intermediate and large neoplastic lymphocytes. Variably-shaped cytoplasmic processes laden with single-stranded nucleic acids (SSNA) were observed for the small and intermediate-sized neoplastic lymphocytes, compared with large neoplastic lymphocytes and the normal lymphocytes; the latter two categories of cells being virtually devoid of similar processes. Prominent cytoplasmic and nuclear clumps of SSNA, indicative of a higher rate of metabolic activity, were also observed within the neoplastic cells compared with fewer and narrower SSNA of the normal cells. CONCLUSION: The comparative relative increases of SSNA in cytoplasmic processes and other cellular areas of small and intermediate-sized neoplastic lymphocytes is reflective of greater metabolic activity in neoplastic cells in general compared with their normal cellular counterparts.

The application of PCR and reverse line blot hybridization to detect arthropod-borne hemopathogens of dogs and cats in Trinidad.

Arthropod-borne diseases are important causes of morbidity and mortality of companion animals in Trinidad. As clinical signs are vague, more sensitive methods to diagnose these diseases based on the polymerase chain reaction (PCR) followed by reverse line blot hybridization (RLB) of amplified products are being developed. An RLB of 14 oligonucleotide probes coupled with polymerase chain-amplified regions of 16S rRNA or 18S rRNA genes of hemoparasites from cats and dogs detected Ehrlichia canis, Anaplasma platys, Babesia canis vogeli, feline mycoplasmas ("Candidatus Mycoplasma haemominutum,"Mycoplasma haemofelis), and some unknown species within the Babesia/Theileria group and the Anaplasma/Ehrlichia tribe. Amplified products were obtained from blood samples collected from 348 dogs and 15 cats. Overall, hemopathogen DNA was detected in 92 (26.4 per cent) dogs and six (40.0 per cent) cats. E. canis (49, 14.1 per cent) and feline mycoplasma (5, 33.3 per cent) DNA were most frequently identified in dogs and cats, respectively. B. canis vogeli (1, 6.7 per cent) and E. canis (1, 6.7 per cent) were also detected in cats. Mixed infections of Anaplasma/Ehrlichia sp. and Babesia sp. were present in five (1.4 per cent) dogs, while mixed infections of the feline mycoplasmas were present in two (13.3 per cent) cats, one of which was also positive for E. canis. Pyrexia was significantly associated with a positive RLB result in dogs (P= 0.00, chi(2), 1 df). This is the first reported application of macro-arraying techniques to detect arthropod-borne hemopathogens of companion animals in the Americas and the first detection of DNA of B. canis vogeli and E. canis in cats in Trinidad.

The application of PCR and reverse line blot hybridization to detect arthropod-borne hemopathogens of dogs and cats in Trinidad.

Arthropod-borne diseases are important causes of morbidity and mortality of companion animals in Trinidad. As clinical signs are vague, more sensitive methods to diagnose these diseases based on the polymerase chain reaction (PCR) followed by reverse line blot hybridization (RLB) of amplified products are being developed. An RLB of 14 oligonucleotide probes coupled with polymerase chain-amplified regions of 16S rRNA or 18S rRNA genes of hemoparasites from cats and dogs detected Ehrlichia canis, Anaplasma platys, Babesia canis vogeli, feline mycoplasmas ("Candidatus Mycoplasma haemominutum,"Mycoplasma haemofelis), and some unknown species within the Babesia/Theileria group and the Anaplasma/Ehrlichia tribe. Amplified products were obtained from blood samples collected from 348 dogs and 15 cats. Overall, hemopathogen DNA was detected in 92 (26.4%) dogs and six (40.0%) cats. E. canis (49, 14.1%) and feline mycoplasma (5, 33.3%) DNA were most frequently identified in dogs and cats, respectively. B. canis vogeli (1, 6.7%) and E. canis (1, 6.7%) were also detected in cats. Mixed infections of Anaplasma/Ehrlichia sp. and Babesia sp. were present in five (1.4%) dogs, while mixed infections of the feline mycoplasmas were present in two (13.3%) cats, one of which was also positive for E. canis. Pyrexia was significantly associated with a positive RLB result in dogs (P= 0.00, chi(2), 1 df). This is the first reported application of macro-arraying techniques to detect arthropod-borne hemopathogens of companion animals in the Americas and the first detection of DNA of B. canis vogeli and E. canis in cats in Trinidad.

Effect of age and gender on haematological and serum chemistry parameters of pigs in Trinidad and Tobago

A total of 361 blood samples were collected from nursey pigs, grower/finishers and adult breeding pigs on 36 farms in Trinidad and Tobago and evaluated for selected haematological parameters and serum chemistry. The erythron and all leukon variables, except eosinophils, were unaffected by gender. Females had higher eosinophil counts than males (P ¡Ü 0.05). Males were found to have higher creatine kinase values than females (770.65 ¡À 55.03 vs. 594.39 ¡À 33.14 U/L, P = 0.006). No differences existed between males and females for the other serum chemistry parameters studied. Age had a msignificant effect on the erythron parameters evaluated; the haemoglobin, haematocrit, and mean corpuscular haemoglobin concentration showed increasing trends with age (P ¡Ü 0.05). Adult breeding animals had significantly lower white blood cell counts and lymphocyte counts than the other age groups ( P > 0.05). Similarly, there was no significant age effect for calcium, bilirubin, alanine aminotransferase, or gamma -glutamyl transferase ( P > 0.05). Potassium and glucose decreased with age whereas sodium increased with age, chloride was lower in grower/finishers than in either the adult or the nursery groups ( P ¡Ü 0.05). Creatinine, total protein and albumin increased with age; globulin and bicarbonate increased significantly from the nursery stage to the grower/finisher stage but decreased to adult values (P ¡Ü 0.05). Alkaline phosphatase was significantly lower in adults than in the other two groups, whereas aspartate aminotransferase was higher in nursery pigs than in adults (P ¡Ü 0.05).

A serological study of Babesia caballi and Theileria equi in Thoroughbreds in Trinidad.

Ninety-three (93) horses were investigated for serum antibodies to Theileria equi (T. equi) and Babesia caballi (B. caballi) using the immunofluorescent antibody test (IFAT). Seventy-seven (82.8%) horses were seropositive; 31 (33.3%) were positive to T. equi compared to 64 (68.8%) to B. caballi while 18 (19.4%) horses were seropositive to both parasites. No significant differences in antibody frequencies among females and males for either T. equi or B. caballi were noted. Differences in seropositivity to B. caballi among age groups were not significant. Antibodies to T. equi were more frequent than to B.caballi in the age group 5 years and over than in the 1-2 and 2-4 years age groups (p<0.05). Unlike T. equi antibodies, B. caballi antibodies in horses in the county of Caroni were significantly less frequent when compared to other counties (p<0.05). Of 18 (19.4%) clinically ill horses, seven (42.9%) had clinicopathological evidence of anemia. Only one-third (6 of 18) horses were positive for the parasite on Wright-Giemsa stained blood smears and anemia was present in only 2. We report here that B. caballi and not T. equi may be the more common agent of piroplasmosis in Trinidad.

Canine histoplasmosis in Trinidad

Canine histoplasmosis was first reported in Trinidad in 1990 (Vet. Diag. Lab: Ann Report). It involved a case of disseminated histoplasmosis in a 5 year-old male Doberman from north-eastern Trinidad. Subsequently, five cases, all classified as the disseminated form of the disease, have been diagnosed in dogs of different breeds, mainly from the northern part of the island. The aetiological agent is a dimorphic fungus, Histoplasma capsulatum which occurs as a yeast in the parasitic phase, but exists as a filamentous mycelin producing microconidia and macroconidia in the saprophytic phase. Histoplasmosis is a zoonosis and has a world-wide distribution. Although in man most cases are asymptomatic, severe illness and death can occur (AU).