One-day-old chickens were transported from Australia to Malaysia and vaccinated orotracheally with an uninactivated vaccine prepared from avirulent Australian V4 strain of Newcastle disease virus (NDV). The vaccination regimes were as follows: group A, once, at 2 weeks old; group B, once, at 3 weeks old; group C, twice, at 2 and at 3 weeks old; group D, direct contact with groups A, B, and C; and group E, indirect contact with groups A, B, C, and D. Group F was unvaccinated controls. Challenge was with NDV virulent Ipoh AF 2240-226 strain, administered at 4 weeks old intramuscularly to 10 chickens in each group and orotracheally to 10 chickens in each group. The remaining chickens were challenged by contact with the inoculated chickens. Group mortalities following challenge were: A, 1/77; B, 1/34; C, 0/39; D, 0/45; E, 6/43; and F, 60/60.
Paralytic poliomyelitis is a constantly rising problem in the developing world. It may take an insiduous endemic "infantile paralysis" behaviour exacting a high toll in the first few years of life, as in Ghana or Burma but on the other hand it may take the form of sudden extensive outbreaks of paralytic disease as in Argentina, Mexico or Malaysia. The developed world has controlled the disease by effectively immunizing a very high proportion of their populations, but those who have not been vaccinated are at risk even in countries with very high coverage, as has been noted in the Netherlands, Sweden, United States of America, etc. There is no reason to have a crippled paralytic child (or adult). Both the live and killed vaccines have been repeatedly shown to be safe and effective. The minute risk incidental to vaccination is more than one hundredfold smaller than the risk from the disease, not only in the developing world but in the developed world as well. Therefore, the question of which vaccine to use is of far less relevance than of how to increase effective coverage with any available vaccine. This does not mean that vaccine control should be relaxed. A health respect should be maintained for the polioviruses used as vaccine sources and great care must be exercised by those undertaking the manufacture or the administration of vaccine.
An experimental oil emulsion Newcastle disease vaccine was evaluated for its efficacy in broiler chickens. A group of chickens vaccinated at one day old with a live lentogenic Newcastle disease vaccine and subsequently revaccinated at three and eight weeks old with the experimental oil emulsion vaccine showed satisfactory haemagglutination inhibition antibody response which persisted for 18 weeks. Between 90 and 100 per cent of the vaccinated chickens were protected when challenged with the velogenic viscerotropic Newcastle disease virus. Although the vaccinated chickens were protected against clinical disease, virus could be isolated from a number of birds. By day 10 to 12 after challenge all the chickens were free from Newcastle disease infection.
A study was carried out at the University Hospital, Kuala Lumpur, Malaysia to determine the age-specific prevalence of measles infection by serology and the age specific - seroconversion rates following measles vaccination. The results show that the percentage of children with passively acquired measles antibodies decreased with increasing age fill three to five months of age. From 12 months of age, the percentage of positivity increased sharply due probably to natural infection. The geometric mean antibody titre was low at birth, but from six months it started to increase. These results indicate that measles infection is common in Malaysia and a small number of children began to acquire natural measles infection from six to eight months of age; however the peak age for the acquisition of measles infection was from 12 months to five years of age. Seroconversion rates following vaccination from nine months of age, ranged from 94-99%. However, the rates and the geometric mean titre were higher among those vaccinated at 11 months of age or older compared with those vaccinated at nine or ten months of age. Based on the above results, it is concluded that the optimum age for measles immunization in Malaysia should be 11 months.
ELISA and immunoblotting techniques were used to examine the humoral immune response to Pasteurella multocida, in bovine sera from Indonesia and Malaysia. Elevated levels of antibody to a crude lipopolysaccharide preparation were found in vaccinated animals. In addition to the response to lipopolysaccharide, antibodies from the vaccinated cattle strongly labelled five to six of the 40 protein bands in this organism.
The food pellet vaccine has been shown to be effective in trials conducted under laboratory and simulated field conditions. The village chickens vaccinated with the food pellet vaccine during the field trial were protected against virulent Newcastle disease virus. The efficacy of the food pellet vaccine in the field was evaluated by challenge trial in which 60 per cent protection was obtained, or by monitoring the incidence of Newcastle disease in vaccinated and unvaccinated birds. There was no report of Newcastle disease outbreaks in the vaccinated birds during the two-year period of the field trial. The ease in administering the food pellet vaccine makes it readily accepted by the farmers.
Meat chickens housed on a commercial broiler farm in Australia were vaccinated once at 10 to 11 days-of-age by aerosol with live V4 Newcastle disease virus (NDV) vaccine. Groups of vaccinated and unvaccinated birds were flown to Malaysia, where they were challenged with a virulent strain of NDV. Survival rates in vaccinated chickens challenged 7, 14, 21 or 31 d after vaccination were 0.47, 0.77, 0.97 and 0.92, respectively. All unvaccinated chickens died due to Newcastle disease (ND) following challenge. Chickens in Australia and Malaysia were bled and the serums tested for haemagglutination-inhibiting (HI) antibody to NDV. Many vaccinated birds with no detectable antibody, and all birds with a log2 titre of 2 or greater, survived challenge. The results showed that this V4 vaccine induced protective immunity in a significant proportion of chickens within 7 d of mass aerosol vaccination. This early immunity occurred in the absence of detectable circulating HI antibody. Non-HI antibody mediated immunity continued to provide protection up to 31 d after vaccination. Almost all vaccinated birds were protected within 3 w of vaccination. It is concluded that the V4 vaccine is efficacious and could be useful during an outbreak of virulent ND in Australia.
The effectiveness of an oil adjuvant vaccine (OAV) incorporating locally isolated strains of Pasteurella haemolytica type 7 and Pasteurella multocida types A and D was compared with that of Carovax (Wellcome Laboratories) in imported cross-bred lambs. The criterion of efficacy was the ability of the vaccines to reduce the extent of pneumonic lesions in vaccinated as against unvaccinated control lambs. The OAV produced at this Institute significantly reduced the lung lesions at P less than 0.05 level compared with its control group when challenged with P. haemolytica alone. However, the vaccine was unsatisfactory against P. multocida or combined P. multocida P. haemolytica challenge. Carovax did not produce any significant reduction in the lung lesions caused by P. haemolytica and/or P. multocida.
A questionnaire was mailed to 1217 dentists whose names appear in the Dentist Register of 1987 in order to assess their awareness and acceptance of hepatitis B vaccine and their pattern of glove usage. Almost all the respondents (99.6%) were aware of the availability of the hepatitis B vaccine yet only 44.8% have received the vaccine. This is in spite of the fact that the majority (61.2%) of the vaccine non-acceptors have no reservations concerning the vaccine. About 71% and 63% of the vaccine-acceptors and non-acceptors respectively believed that the risk of their contracting hepatitis B was high or very high. About 22% of the vaccine non-acceptors never used gloves when treating patients as compared to 9% among vaccine acceptors. Overall, about 78% of the respondents have experienced needleprick injuries in the 3 years preceding the survey.
To verify the actual immunisation coverage in Kuala Lumpur, City Hall Health Department and the Malaysian Paediatric Association (NGO ) carried out a survey. The survey revealed that the immunisation coverage determined at the child's first birthday for BCG was 95%, DPT 3 94%, OPV 3 94%, and measles = 27% (59% at 2 years). These figures correspond closer to City Hall's estimated coverage rather than the rates projected by the Ministry of Health. The main reasons for immunisation failure were, child ill 31.8% (not brought = 20.1%, brought but not given vaccine 11.7%), lack of information 28.6%, lack of motivation 9.1%, mother too busy 9.1%. Measles immunisation coverage at 1 year was low because of wrong information on schedules. Tetanus toxoid immunisation coverage of pregnant women was low. Only 27% of children were protected against neonatal tetanus although 97% of pregnant women received antenatal care and 50% had attended other health facilities as well during pregnancy. Private medical practitioners were responsible for more than 40% of all immunisations but were not submitting returns to the Health Department. Recommendations to improve immunisation coverage include education and motivation of the public and also doctors and health personnel on prevention of missed opportunities, contraindictions to immunisation and correct schedules. (Copied from article).
Mass vaccination of all newborns against hepatitis B virus infection has been implemented in Malaysia since January 1989. The significance of perinatal transmission of hepatitis B virus and the prevention of the disease are discussed. Routine screening of 6443 mothers in the University Hospital showed an overall carrier rate of 1.9%; whilst this was high amongst the Chinese (4.7%), a significant number of Malays were also infected (1.6%). The mechanism of perinatal transmission of hepatitis B and the important role of routine screening of antenatal mothers in eradicating the disease are discussed.
The last confirmed case of poliomyelitis in West Malaysia was in 1986', and over the past few years, we have condescendingly associated polio with other developing countries. Recently, 2 children with acute flaccid paralysis (AFP) were confirmed as cases of poliomyelitis due to a wild strain of the virus. This implies a failure of the immunisation programme to contain the spread of the wild virus (Hall). However, if we look at the WHO standard case definition of polio virus infection (appendix 1) it is possible that we could have missed a few cases over the last 6 years. At this juncture a brief clinical summary of the 2 cases and a discussion of the differential diagnosis may be useful. (Copied from article).
Poliomyelitis in Malaysia has not been reported since 1986. We report two cases of poliomyelitis in non-immunized children whose parents, though relatively educated, opted not to vaccinate their children for socio-cultural reasons. This recent trend may interfere with our attempts to eradicate poliomyelitis globally by the year 2000. The clinical features, pathophysiology and differential diagnosis are discussed.
The objective of the study is to investigate the extent of preventive and promotive health care in the ambulatory management of paediatric gastroenteritis in an incompletely immunised child using the simulated patient methodology. Only 44% of doctors explained to the fathers the nature of their child's ailment. 75% of clinicians prescribed oral rehydration solution but only 4% met the Gold Standard. The questionnaire survey showed that doctors rated immunisation as a very important health message to disseminate to all parents. But only 3% of doctors in the study advised parents to complete each child's immunisation once he is well. The extent of preventive and promotive health care in ambulatory paediatric practice in the Klang Valley is very low. (Copied from article).
The relationship between the standard passive mouse protection test or serum antibody titres measured by indirect haemagglutination or enzyme-linked immunosorbent assays and active protection in buffaloes immunized with different types of haemorrhagic septicaemia bacterins was investigated. Groups of 2-3 buffaloes were immunized with the bacterins currently in use in Asia, viz., broth bacterin (BB), alum precipitated vaccine (APV) and oil adjuvant vaccine (OAV) either subcutaneously (BB, APV) or intramuscularly (OAV) and challenged subcutaneously with virulent organisms at different periods post-immunization. Although the passive mouse protection and indirect haemagglutination tests carried out with the pre-challenge sera from vaccinated buffaloes revealed no relationship with active protection in buffaloes, a relationship was observed between the ELISA antibody titres and protection. In contrast, a dose-response relationship was observed between the homologous active and passive mouse protection test.