The data from our 1968-69 influenza vaccine field trials are anlaysed and pre-challenge haemagglutinin and neuraminidase serum antibodies are evaluated as indices of protection. Prevention of flu-like disease, fever, confinement to bed, and/or seroconversion to Hong Kong was significantly related to post-vaccine A/Hong Kong/68(H3N2) haemagglutination-inhibition (HI) titres. Prevention of diseas...

newcastle disease is one of the most important diseases of poultry. it usually causes a great loss inpoultry industry and domestic village chickens. since domestic chickens in villages are free ranging for food,the chance of their contact with wild birds that may act as reservoirs is high. to determine the role ofdomestic chickens in the epizootiology of newcastle disease virus in villages of i...

Newcastle disease causes many economic losses to the poultry industry in most countries. This disease is endemic in Iran. Backyard poultry is considered the reservoir of Newcastle virus; however, there is either no vaccination program against Newcastle, or it is performed in a restricted manner. Commercial live vaccines are inactive and sensitive to temperature; moreover, vaccine delivery to vi...

An experimental inactivated oil-emulsion H9N2 avian influenza vaccine was formulated with 3 parts ofinactivated avian influenza antigen A/Chicken/Iran/101/1998(H9N2) emulsified in 7 parts of oil adjuvant.Twelve week-old specific pathogen-free (SPF) chickens were divided into seven groups of 10 birds. Sixgroups were vaccinated with 1, 1/10th, 1/50th, 1/100th, 1/200th and 1/400th field dose of th...

Rubella contracted in early pregnancy is associated with a high frequency of congenital anomalies in the infant. Viral transmission occurs in overt as well as occult maternal illness with or without a rise in maternal rubella antibody titres. It is thus both difficult and important to determine whether the fetus has become infected in utero. One approach is to isolate rubella virus from amnioti...

BACKGROUND Antibodies directed against haemagglutinin, measured by the haemagglutination inhibition (HI) assay are essential to protective immunity against influenza infection. An HI titre of 1:40 is generally accepted to correspond to a 50% reduction in the risk of contracting influenza in a susceptible population, but limited attempts have been made to further quantify the association between...

The single radial haemolysis (SRH) technique detected anti-B/HK/8/73 HA antibody rises in 59-85% of paired sera from persons immunized with different influenza vaccines. In contrast, analysis of the same sera by the haemagglutination inhibition (HI) test indicated significant antibody rises in only 27-54% of paired sera. High levels of antibody were detected to influenza B/HK/8/73 and B/Singapo...

Discrimination between primary and secondary dengue infections is important, as the possibility of DHF is more in secondary infection. Therefore, there is need to develop a test that can distinguish between primary and secondary serological responses. The traditionally-used haemagglutination inhibition (HI) test, which is recommended by the World Health Organization, is complicated to perform. ...

Ten species of nonhuman primates in West African habitat were analysed for variolavaccinia subgroup haemagglutination-inhibition (HI) and neutralization antibodies. The animals were taken in 27 different sampling zones in parts of the Ivory Coast, Mali, and Upper Volta. Of the 195 tested, 15 (8%) had elevated HI antibodies after nonspecific reactions were reduced with potassium periodate pretre...

Psittacine beak and feather disease (PBFD) is a common viral disease of wild and captive psittacine birds characterized by symmetric feather loss and beak deformities. The causative agent, beak and feather disease virus (BFDV), is a small, circular single-stranded DNA virus that belongs to the genus Circovirus. BFDV can be detected by PCR or the use of haemagglutination (HA) and haemagglutinati...