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Biomedical subjects

M Isaäcson

Publications and source records attributed to M Isaäcson.

At least 19 recordsLinked to original sources
PubMed2001

Viral hemorrhagic fever hazards for travelers in Africa.

This short review covers 6 viral hemorrhagic fevers (VHFs) that are known to occur in Africa: yellow fever, Rift Valley fever, Crimean-Congo hemorrhagic fever, Lassa fever, Marburg virus disease, and Ebola hemorrhagic fever. All of these have at one time or another affected travelers, often the adventurous kind who are "roughing it" in rural areas, who should therefore be made aware by their physicians or travel health clinics about their potential risk of exposure to any VHF along their travel route and how to minimize the risk. A significant proportion of VHF cases involving travelers have affected expatriate health care workers who were nosocomially exposed in African hospitals or clinics. The VHFs are associated with a high case-fatality rate but are readily prevented by well-known basic precautions.

Africa↗
PubMed2000

An outbreak of hepatitis E in Northern Namibia, 1983.

In 1983 in Namibia's Kavango region, epidemic jaundice affected hundreds of people living in settlements lacking potable water and waste disposal facilities. Many were Angolan refugees. The disease, which after investigation was designated non-A non-B hepatitis, was most common in males (72%), in persons aged 15-39 years, and was usually mild except in pregnant women, who incurred 6 (86%) of the 7 fatal infections. Fifteen years later, archived outbreak-associated samples were analyzed. Hepatitis E virus (HEV) was detected by reverse transcription-polymerase chain reaction in feces from 9 of 16 patients tested. Total Ig and IgM to HEV were quantitated in serum from 24 residents of an affected settlement at the outbreak's end: 42% had IgM diagnostic of recent infection and 25% had elevated total Ig without IgM, consistent with past HEV infection. The Namibia outbreak was typical hepatitis E clinically and epidemiologically. This first report of hepatitis E confirmed by virus detection from southern Africa extends the known range of HEV and highlights its risk for refugees.

Adolescent↗
PubMed1999

The effect of iron on the toxigenicity of Vibrio cholerae.

In vitro and in vivo studies were conducted to assess the response of cholera toxin (CT) production to increasing iron concentrations in an aquatic environment. Production of CT by seven of eight Vibrio cholerae strains tested, including the Bengal strain (O139), was significantly enhanced in the presence of iron concentrations of 1.0 and 10 g/L. The exception (El Tor Ogawa) had a significant CT response only in the presence of 10 g of iron/L. Enhancement of CT production also occurred at iron concentrations less than 1.0 g/L, but not to a statistically significant degree. The high iron concentrations, which in this study were found to stimulate CT production, have been described by others in association with sediments, water plants, and chitinous fauna. Other investigators have shown a predilection by V. cholerae to attach to these sites in the aquatic environment. The importance of excess in vivo iron with respect to the pathogenicity of several gram-negative bacilli is well recognized. However, the possible impact of environmental iron on the in vitro toxigenicity of a microorganism, in this case V. cholerae in its aquatic environment, is to the best of our knowledge a new finding with important epidemiologic implications. These findings, coupled with the fact that iron concentration is considerably enhanced in industrially polluted waters and sediments, may reflect a causal link between the concurrent global upsurge of industrialization and pandemic occurrence of cholera during the latter half of the 20th century. Enhanced toxigenicity may also cause clinical disease following ingestion of lower than usual infective doses of cholera vibrios, thereby increasing the incidence of symptomatic cases and, possibly, of severe cases.

Animals↗
PubMed1994

Investigation of contaminated parenteral nutrition fluids associated with an outbreak of Serratia odorifera septicaemia.

An outbreak of fatal septicaemia caused by Serratia odorifera biotype 1 involved infants at several hospitals; the common vehicle of infection was contaminated parenteral nutrition fluid. The transfusate had been made up in a flexible film isolator system. The implicated organism was recovered from surfaces inside the isolator, despite routine decontamination procedures having been carried out shortly before. Our investigation into the origin of contamination revealed several shortcomings in the infusate compounding process. We noted deficiencies in cleaning and decontamination procedures, and in storage and sterility testing policies, but the origin and mechanism of the contamination were unclear. Withdrawal of parenteral nutrition products and revision of decontamination procedures terminated the outbreak. The efficacy of peracetic acid treatment of flexible film isolators, given the circumstances of this outbreak, may need further investigation. Regular training and assessment of admixture technicians is important.

Bacteremia↗
PubMed1994

Enhancement of microbiological safety levels of aseptically admixed total parenteral nutrition solutions through low-dose gamma irradiation.

This study was undertaken to determine the effect of low-dose gamma irradiation on aseptically admixed total parenteral nutrition (TPN) solutions to which large inocula of three test bacterial species were added. Microbiological safety levels were quantified in terms of sterility assurance levels (SALs), indicating the probability of contamination occurring expressed as 10-n. The radiation sensitivity (D10 values) of test bacteria in TPN solutions inoculated with a series of bacteria recognized as common contaminants of these products, was determined. Attainable SALs of TPN solutions containing test bacteria were subsequently calculated from the D10 values. Results showed that a minimum absorbed radiation dose as low as 1.5 kGy improved the SAL of aseptically prepared TPN solutions from a probability value of 10(-3) to a value of less than 10(-8) for the microorganisms investigated. At an absorbed dose as high as 8.3 kGy, no measurable changes in amino acid, electrolyte, glucose and lipid components of the solutions were detected. These findings have important implications for the enhancement of microbiological safety levels of aseptically prepared intravenous fluids in general.

Amino Acids↗
PubMed1992

Histologically diagnosed cancer in South Africa, 1987.

The National Cancer Registry collects information on cases of histologically diagnosed cancer via a country-wide network of private and public pathology laboratories. Minimal age-standardised incidence rates (ASIR, world standard) per 100,000, excluding basal and squamous cell skin cancers, for white, coloured and Asian males were 195.9, 76.2 and 82.9 respectively, and for females 161.8, 68.8 and 81.1 respectively. The oesophagus was the commonest site of cancer in black males, comprising 25.2% of all cancers in this group, and the cervix was the commonest site in black females (31.6%). Basal and squamous cell skin cancers were the leading cancers in white males (ASIR 191.9) and females (ASIR 96.9). Despite limitations, especially in data for blacks, rates for oesophageal, cervical and skin cancers rank among the highest in the world. The lung was the leading site of cancer in coloured males (ASIR 13.8) but this cancer is underestimated in all populations. Reasons for underestimation of cancer incidence include the use of non-histological methods for diagnosing cancer (cytology, radiographs, clinical examination) and variable access of populations, especially blacks and coloureds, to laboratory diagnostic facilities.

Female↗
PubMed1991

Sporotrichosis following a rodent bite. A case report.

A ten year old boy developed lymphocutaneous sporotrichosis following a wild rodent bite. The infection was successfully treated with potassium iodide. Sporotrichosis in humans has followed bites, pecks and stings inflicted by a variety of animals, birds and insects. Many species of animals are susceptible to infection by Sporothrix schenkii, but transmission from infected animals to man is uncommon.

Animals↗
PubMed1991

Immune responses of two Mastomys sibling species to Yersinia pestis.

This study assessed the in vitro cell-mediated immune responses of Mastomys natalensis, with a diploid chromosome number of 2n = 32, and Mastomys coucha, with a diploid chromosome number of 2n = 36, to Yersinia pestis. Splenic mononuclear (MN) cells of uninfected M. natalensis proliferated in response to crude fraction 1 of Y. pestis and two subfractions derived from fraction 1 in vitro. Proliferation was dose dependent and followed the time kinetics of other well-known mitogens. Further characterization of the two fractions revealed similar protein profiles in sodium dodecyl sulfide-polyacrylamide gel electrophoresis and indicated a heat-stable protein of 25 kDa responsible for the mitogenic activity. No such response was observed with MN cells from M. coucha. The unresponsiveness of M. coucha-derived MN cells appears to be related to an inability to respond to Y. pestis organisms. The results may help explain the relative resistance and susceptibility of M. natalensis and M. coucha to Y. pestis infection.

Animals↗
PubMed1989

Survival of Vibrio cholerae in African domestic water storage containers.

Although much has been published about growth of Vibrio cholerae in natural sources of water, little or nothing has been written on its survival in common household water storage containers. This study compared the behaviour of the El Tor and Classical biotypes of V. cholerae in different containers commonly used in Africa for domestic water storage. These included traditional clay pots, wooden barrels, galvanised iron drums (corroded and non-corroded) and plastic (polyethylene) drums. The findings are considered to be of public health interest with reference to selection of the most suitable containers for the storage of water drawn from a treated source. Although survival of V. cholerae was much shorter in clay pots than in any of the other containers, the numbers of viable V. cholerae were higher than in non-corroding iron drums and plastic drums. The clay pots, being porous, also showed a tendency to constant outward seepage of water which, when collected, was also shown to harbour cholera bacilli. These containers are therefore considered hazardous as pathogens in the stored water are easily disseminated to contaminate either hands or food prepared in the vicinity. The longest survival occurred in damaged metal drums. Presence of other bacteria greatly inhibited survival of V. cholerae. The response of the two biotypes was much the same in all the experiments.

Africa↗
PubMed1989

Airport malaria: a review.

Cases of malaria occasionally arise among individuals who have never visited a malarious area. Such patients, who also lack a history of blood transfusions or intravenous drug abuse, are usually shown to have "airport malaria". Most reports of airport malaria consist of case histories, although some epidemiological reviews have also appeared. The clinical and epidemiological features of 29 cases of airport malaria that were reported in Europe from 1969 to 1988 are reviewed here. Although airport malaria is rare, the apparent absence of risk factors for the disease in a patient's history can result in delays in diagnosis and appropriate treatment. Tests to exclude malaria should therefore be carried out on patients who work at or live near an international airport and who present with acute febrile illnesses.

Adolescent↗
PubMed1988

Health aspects of the use of recycled water in Windhoek, SWA/Namibia, 1974-1983. Diarrhoeal diseases and the consumption of reclaimed water.

The introduction of the use of reclaimed water in Windhoek, SWA/Namibia, prompted an epidemiological study to assess the health effects, if any, of its consumption. Analysis of more than 15,000 episodes of diarrhoeal disease during the period August 1976-March 1983 showed that their incidence in whites of similar socio-economic status was marginally lower in persons supplied with reclaimed water than those with water from conventional sources. Incidence rates were significantly higher in blacks and in coloureds, all of whom received conventional water only. Age-specific incidence rates in children of the various ethnic groups also showed differences characteristically associated with socio-economic stratification. It is concluded that the consumption of reclaimed water does not increase the risk of diarrhoeal diseases caused by waterborne infectious agents.

Adolescent↗