ABSTRACT
Two strains of Bhanja (BHA) virus, an ungrouped arbovirus, were isolated from Haemaphysalis punctata ticks collected from sheep on the island of Brac in the Yugoslavian Adriatic. Serologic testing gave evidence of the endemicity of BHA virus on the island, and antibody prevalence rates were high for both man (35.8%--ranging locally to 61.3%) and sheep (100%). No antibody was found in 82 small mammals tested. Evidence of a natural cycle involving ticks and sheep, the potential significance of this virus for man and for animals of agricultural importance, and factors related to its epidemiology are discussed.
Subject(s)
Arboviruses/isolation & purification , Ticks/microbiology , Animals , Antibodies, Viral , Arboviruses/immunology , Humans , Mice , Rats , Sheep/immunology , YugoslaviaABSTRACT
The role of viruses in respiratory diseases of young children in Uganda was studied. A viral etiology was established in 36% of the infections investigated. The most important pathogens were found to be respiratory syncytial virus and parainfluenza viruses, which were responsible for 26% of infections investigated. They caused both upper and lower respiratory tract diseases. There was little or no seasonal variation in the etiology of these infections. Adenoviruses were found to be less important and were etiologically related to only 4% of respiratory disease cases. Influenza viruses and enteroviruses were also found to be associated with respiratory infections. However, they were less frequent and their role was insignificant. The role of multiple virus infections was also insignificant.
Subject(s)
Respiratory Tract Infections/microbiology , Virus Diseases/etiology , Acute Disease , Adenoviruses, Human/isolation & purification , Child, Preschool , Enterovirus/isolation & purification , Enterovirus B, Human/isolation & purification , Female , Humans , Infant , Infant, Newborn , Male , Mycoplasma/isolation & purification , Poliovirus/isolation & purification , Respiratory Syncytial Viruses/isolation & purification , Respirovirus/isolation & purification , Simplexvirus/isolation & purification , Uganda , World Health OrganizationABSTRACT
A virologically controlled field trial was conducted with live monovalent type 1 poliovirus vaccine in children aged 3-30 months living in a rural area of Uganda, in an attempt to find out the reason for the poor efficacy of such vaccine often observed in countries with a warm climate. Groups of breast-fed and of artificially fed infants received the vaccine orally, either alone or mixed with horse serum prepared against partly purified human gamma-globulin. Irrespective of the diet, the "take rate"-measured by the rates of vaccine virus excretion and of antibody conversion-was found to be poor when the vaccine was given alone but satisfactory when it was given together with the horse antiserum. However, the extent and duration of vaccine virus multiplication in the intestinal tract proved to be limited and the mean antibody level elicited by the vaccination, irrespective of the schedule of vaccine administration, was low. These results, besides indicating that breast-feeding does not influence the efficacy of vaccination in the age groups studied, revealed the presence of an inhibitor in the alimentary tract. This inhibitor acts against the multiplication of vaccine virus, which may be blocked by antibodies in the horse antiserum for a limited period at the time of vaccination. Interference between the enteroviruses and the vaccine strain was also found to be responsible for decreasing the efficacy of vaccination, though its role was secondary to that of the inhibitor. Revaccination experiments showed that the effects of both inhibitor and interference may be overcome by repeated administration of the vaccine.
