RESUMO
In a single complete epidemic in St Lucia, an island too small to support constant clinical pertussis, the pertussis case rates in small communities (villages and small towns) with differing levels of vaccination coverage of young children were compared. The association between greater vaccination coverage and greater herd immunity was clear, despite the imperfect protection given to individuals. An analysis in terms of population dynamics is evidence against the theory that endemic subclinical pertussis maintains transmission in a highly vaccinated population. We suggest that with a homogeneous vaccination coverage of 80 percent of 2-year-old children pertussis might be eradicated from the island, and that is a practical experiment. (Summary)
Assuntos
Humanos , Lactente , Pré-Escolar , Criança , Adolescente , Vacina contra Coqueluche/imunologia , Vacinação , Coqueluche/imunologia , Surtos de Doenças/prevenção & controle , Imunidade , Dinâmica Populacional , Probabilidade , Santa Lúcia , Coqueluche/prevenção & controle , Coqueluche/transmissãoAssuntos
Gravidez , Pré-Escolar , Criança , Adolescente , Adulto , Idoso , Cães , Técnicas Imunoenzimáticas , Larva Migrans Visceral/diagnóstico , Toxocara , Porto Rico , Retinite/etiologia , Solo , Gravidez , Imunoglobulina E , Imunoglobulina G , Larva Migrans Visceral/epidemiologia , Larva Migrans Visceral/transmissão , Imunidade , Endoftalmite/etiologia , Oftalmopatias/etiologia , Granuloma/etiologiaRESUMO
Data obtained at the Bush Bush Forest field station in the Nariva Swamp, eastern Trinidad, indicated the continuous presence there of three Guama-group agents - Bimiti, Catu, and Gauma - all apparently dependent on the same rodent host and vector populations. This suggested the possibility that the antigenic relation of these viruses might influence their epidemiology. The question was investigated by examining the effect of cross-immunity on circuling-virus levels in captive-reared Oryzomys laticeps and zygodontomys brevicauda, two species of rodent that are natural hosts for these viruses. Bimiti virus was circulated at lower levels in nonimmune Zygodontomys than were the other two viruses, and in cross-immunized zygodontomys, Bimiti-virus levels were still lower and occasionaly undetectable. Catu viremia reached high titers in both nonimmune Oryzomys and Zygodontomys, and even in cross-immunized rodents, titers often reached 2.4 to 3.3 log LD50. Guama viremia in nonimmune Oryzomys and Zygodontomys was of the same order as that of Catu virus, but in cross-immunized rodents it was often completely suppressed. These data suggest that when hosts are scarce Catu virus would be affected least and Guama virus most. The experimental findings are compared with field observation. (AU)
Assuntos
21003 , Arbovírus/imunologia , Doenças dos Roedores/imunologia , Reações Antígeno-Anticorpo , Vetores de Doenças , Testes de Hemaglutinação , Imunidade , Camundongos , Suspensões , Trinidad e Tobago , Cultura de VírusRESUMO
In the year 1925 paralytic rabies appeared among certain animals in the island of Trinidad, and in 1929 affected human beings. Human beings bitten by vampire bats developed sensory symptoms at the site bitten, followed by paralysis and death. Vampire bats by histological examination, animal inoculation, cross-immunity, and serum neutralization tests have been found infected with the virus of rabies. The conclusion is drawn that the vampire bat (Desmond rotundus murinus Wagner, 1840) is the transmitting agent of the disease in man and animals. (Summary).
