AIDS and tuberculosis

The diagnostic and therapeutic implications of human immunodeficiency virus (HIV) infection and tuberculosis in South Africa, where tuberculosis remains a major health problem, are reviewed. Mycobacterium tuberculosis is a high-grade pathogen and is able to establish infection early in immunodeficiency. With HIV infection showing significant entry into the heterosexual population in the RSA, an increasing number of cases with both infections can be expected to occur. The radiological appearance in combined infection is variable, ranging from a formal cavitatory picture to the more common finding of diffuse pulmonary infiltration. Intrathoracic adenopathy is a more specific sign of tuberculosis in HIV infection, since it is not associated with persistent generalised lymphadenopathy and pulmonary opportunistic infections, such as Pneumocystis carinii pneumonia. Intercurrent pneumonic infections and other pulmonary manifestations of HIV disease render the interpretation of new infiltrates on chest radiography problematical. Tuberculin skin testing remains useful in HIV infection and should be performed in all HIV-infected patients. The value of tuberculosis serology still remains questionable. Standard antituberculosis drug regimens are effective, but maintenance treatment must be continued for life and should include isoniazid and rifampicin. BCG vaccination is recommended routinely at birth in infants with HIV infection and for asymptomatic HIV-infected individuals who have not previously been immunised.     

Poliomyelitis outbreak in Natal/KwaZulu, South Africa, 1987-1988. 1. Epidemiology.

An epidemic of type 1 poliomyelitis occurred in Natal/KwaZulu in the eastern part of South Africa between December 1987 and November 1988. 412 poliomyelitis cases were reported, of whom 74% were younger than 5 years. The case-fatality rate was 8%. It is suggested that massive floods, experienced in the area 2 months earlier, triggered the outbreak.     

AIDS and South Africa--towards a comprehensive strategy. Part II. Screening and control

In this, the second of a three-part series of articles in which we propose steps towards a comprehensive strategy for the control of HIV infection, we consider controversies relating to screening for HIV, the indications for and desirability of mandatory testing of certain groups at risk, and the place of voluntary testing in the control of HIV transmission and infection. Key recommendations are that mandatory testing of donors of blood and other vital tissues, patients on haemodialysis and haemodialysis unit staff is justified, and that children put up for adoption may require testing. We make further recommendations regarding HIV testing as a prerequisite for life insurance and recommend that voluntary testing be offered, supported by adequate pre- and post-test counselling. We consider that all health care workers should accept as their moral obligation the care and management of HIV-infected individuals, and that they should be adequately educated and skilled in such work. These recommendations were reached largely by consensus, although there were occasions when individual authors condoned recommendations with which they did not personally agree.     

腹部外科常见感染性疾病的病原菌及药敏试验研究

为了了解本地区本医院腹部外科感染性疾病病原菌的构成比和药物敏感率的变化,指导临床用药,我们采用美国BD公司生产的6B和7D两种增菌瓶采集标本和培养细菌,并用该公司生产的生化板和药敏板,对1994～1996年269例常见的普外科感染性疾病患者的手术标本进行前瞻性的细菌培养和药敏试验研究.     

Enhancement of antigen incorporation and infectivity of cell cultures by human rotavirus.

Infection of cell cultures with human rotavirus preparations was attempted and the effects of trypsin and low-speed centrifugation on antigen incorporation, as demonstrated by immunofluorescence and radioimmunoassay, were determined. In addition, the effect of viral aggregation on antigen incorporation was investigated by filtering viral preparations. Four strains of human rotavirus were employed, and the results were compared to those obtained with two tissue culture-adapted animal rotaviruses. Centrifugation and trypsin appeared to have little or no effect on infectivity of the tissue culture-adapted (simian rotavirus) or -adaptable (Nebraska calf diarrhea virus) strains, whereas centrifugation and viral aggregation appeared to be essential for the human viruses. In addition, trypsin enhanced antigen incorporation of the human strains to some extent. Infectivity for cell cultures and in vitro human rotavirus protein formation was demonstrated by [35S]methionine incorporation, and the specificity of this human viral protein was established by radio-immunoprecipitation.     

Variance in rotavirus infection rates in different urban population groups in South Africa

Rotavirus infection in black infants contrasts markedly with that of white infants in being much less common and showing no seasonal variation. In this multicentre study in Johannesburg, the aetiology of winter infantile gastroenteritis in black, coloured, and white infants was investigated. Stools were examined by electron microscopy and also by enzyme-immunoassay to detect subparticular antigen which may be missed by electron microscopy in patients presenting late in the course of the illness. Stools were also examined bacteriologically by conventional techniques. Rotavirus was the most common pathogen in all three population groups with bacteria playing a relatively minor role. Striking differences were observed in the rotavirus rates between the three groups. Infection in the whites was five times more common than in the blacks (60% versus 12%) with the coloureds intermediate at 40%. The hypothesis was put forward that the relative protection of the black population may be due to a greater degree of colonization of neonates, thus inducing protection against symptomatic infection at the target age of 6 to 24 months. This may well have important implications in immunoprophylaxis. The reason for the lack of seasonal variation in the black population is still unclear.     

Differentiation of primary cytomegalovirus infection from reactivation using the urea denaturation test for measuring antibody avidity

Cytomegalovirus (CMV) is probably the most common agent of prenatal infection of the newborn, and one of 20 congenitally infected newborns shows serious symptoms. It was therefore considered important to be able to differentiate primary CMV from reactivation in pregnant females. A urea denaturation test was used to distinguish primary from secondary rubella infection in which the urea is included in the wash step of the standard IgG ELISA. This resulted in the removal of low-avidity antibodies, which are the antibodies produced early in infection. A group of CMV IgM-negative and -positive sera were tested, and all but one showed moderate to high avidity, with an avidity index reading of more than 30%. Among a group of babies 3-12 months of age, who were CMV IgM positive, 55% (16 of 29) showed low-avidity CMV antibodies. A small group of renal transplant patients and patients with clinically and laboratory-confirmed CMV gave more or less predicted avidity index results. It appears that, with the method used at this laboratory, the urea denaturation test can be applied to CMV to determine primary infection or reactivation in the majority of cases.