Potential for Scombroid Poisoning from Ingestion of Selar crumenophthalmus Due to Increased Histamine Levels in Grenada, West Indies.

ABSTRACT: In scombroid poisoning, a seafood-associated disease, consumption of fish that contains high levels of histamine results in allergy-like symptoms that range from mild to occasionally severe. To date, there is no published information on scombroid poisoning from Selar crumenophthalmus on the Caribbean island of Grenada, West Indies. S. crumenophthalmus is of particular interest because it is a common and heavily consumed fish that has been implicated in scombroid poisoning in Hawaii. Preliminary data on S. crumenophthalmus in Grenada have demonstrated the presence of Photobacterium damselae, a bacterium associated with scombroid poisoning. The present study further tested S. crumenophthalmus purchased in Grenada for factors that would indicate the potential for scombroid poisoning, including increased histamine levels in fish muscle and DNA evidence of bacteria associated with scombroid poisoning. Histamine levels between 7,160 and 66,688 ppm were found after temperature abuse at 37°C for 19 h; this far exceeds the acceptable limit for the United States (50 ppm) and the European Union (100 to 200 ppm). Even after 4 h of incubation at ambient temperature (28.9°C) during a time-point study, histamine levels exceeded U.S. acceptable limits (>50 ppm), and five samples used for temperature-abuse studies had elevated histamine levels (ranging from 141 to 2,510 ppm) at 0 h. PCR and sequence analysis of bacteria in temperature-abused fish identified P. damselae and Morganella morganii, which are histamine-producing bacteria known to be implicated in scombroid poisoning. These results suggest the potential for scombroid poisoning in Grenada and the need for promoting awareness about this disease.

Identification of Helminth Parasites from Selar crumenophthalmus in Grenada, West Indies.

HIGHLIGHTS: Helminths in Selar crumenophthalmus fish were identified by PCR. Two helminth taxa were identified: Anisakis typica and an unknown acanthocephalan. Neither taxon of helminth identified is zoonotic. To our knowledge, this is the first report of either type of helminth in fish in Grenada.

Treatment of canine-generalized demodicosis: a blind, randomized clinical trial comparing the efficacy of Advocate(Bayer Animal Health) with ivermectin.

Advocate (moxidectin 2.5% + imidacloprid 10%) is a multiparasiticidal agent authorized for treating canine demodicosis in many countries. This blind, randomized clinical trial assessed the efficacy of Advocate at varying treatment intervals and compared it with that of oral ivermectin. Fifty dogs with generalized demodicosis were randomly assigned to one of four treatment groups: oral ivermectin (500 microg/kg once daily), Advocate applied at the authorized dose monthly (ADV1), every 2 weeks (ADV2) or weekly (ADV4). Each dog was evaluated every 4 weeks for 4 months or until negative scrapings at all sites resulted on two successive evaluations (parasitological cure). Miticidal efficacy was determined through deep skin scrapings taken from the same three sites on each occasion. Total numbers of live and dead adult mites, juveniles and eggs were determined. Thirty-five dogs completed the 4-month trial. Parasiticidal efficacy was assessed using several parameters including reduction in live adult mite counts. ancova analysis for this parameter confirmed that there were differences in efficacy among the treatment groups (P < 0.002). Tukey-Kramer all pairwise multiple comparison tests revealed that ADV4 was more effective than ADV1 (P = 0.016). Ivermectin was more effective than ADV1 (P = 0.003). Both ivermectin and ADV4 showed clinically substantial reductions in adult mite counts (89% for ADV4 and 98% for ivermectin). In conclusion, the efficacy of Advocate increased with the rate of application and weekly application may represent a new approach to the treatment of caninegeneralized demodicosis.

Prevalence of Ehrlichia canis, Anaplasma platys, Babesia canis vogeli, Hepatozoon canis, Bartonella vinsonii berkhoffii, and Rickettsia spp. in dogs from Grenada.

To identify the tick-borne pathogens in dogs from Grenada, we conducted a serologic survey for Ehrlichia canis in 2004 (104 dogs) and a comprehensive serologic and molecular survey for a variety of tick-borne pathogens in 2006 (73 dogs). In 2004 and 2006, 44 and 32 dogs (42.3% and 43.8%) were seropositive for E. canis, respectively. In 2006, several tick-borne pathogens were identified by serology and PCR. DNA of E. canis, Anaplasma platys, Babesia canis vogeli, Hepatozoon canis, and Bartonella sp. were identified in 18 (24.7%), 14 (19.2%), 5 (7%), 5 (7%), and 1 (1.4%) dogs, respectively. Six (8.2%) dogs were seropositive for Bartonella vinsonii subsp. berkhoffii. All dogs were seronegative and PCR-negative for Rickettsia spp. Coinfection with two or three pathogens was observed in eight dogs. Partial 16S rRNA E. canis and A. platys sequences were identical to sequences in GenBank. Partial 18S rRNA gene sequences from the Grenadian H. canis were identical to each other and had one possible mismatch (ambiguous base) from H. canis detected from Spain and Brazil. Grenadian B. c. vogeli sequences were identical to B. c. vogeli from Brazil and Japan. All of the detected pathogens are transmitted, or suspected to be transmitted, by Rhipicephalus sanguineus. Results of this study indicate that dogs from Grenada are infected with multiple tick-borne pathogens; therefore, tick-borne diseases should be included as differentials for dogs exhibiting thrombocytopenia, leukopenia, fever, or lethargy. One pathogen, E. canis, is also of potential public health significance.