Infectious Diseases - Research Publications

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    Antibody to Plasmodium falciparum Variant Surface Antigens, var Gene Transcription, and ABO Blood Group in Children With Severe or Uncomplicated Malaria
    Barua, P ; Duffy, MF ; Manning, L ; Laman, M ; Davis, TME ; Mueller, I ; Haghiri, A ; Simpson, JA ; Beeson, JG ; Rogerson, SJ (OXFORD UNIV PRESS INC, 2023-10-18)
    BACKGROUND: Antibodies to variant surface antigens (VSAs) such as Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) may vary with malaria severity. The influence of ABO blood group on antibody development is not understood. METHODS: Immunoglobulin G antibodies to VSAs in Papua New Guinean children with severe (n = 41) or uncomplicated (n = 30) malaria were measured by flow cytometry using homologous P falciparum isolates. Isolates were incubated with ABO-matched homologous and heterologous acute and convalescent plasma. RNA was used to assess var gene transcription. RESULTS: Antibodies to homologous, but not heterologous, isolates were boosted in convalescence. The relationship between antibody and severity varied by blood group. Antibodies to VSAs were similar in severe and uncomplicated malaria at presentation, higher in severe than uncomplicated malaria in convalescence, and higher in children with blood group O than other children. Six var gene transcripts best distinguished severe from uncomplicated malaria, including UpsA and 2 CIDRα1 domains. CONCLUSIONS: ABO blood group may influence antibody acquisition to VSAs and susceptibility to severe malaria. Children in Papua New Guinea showed little evidence of acquisition of cross-reactive antibodies following malaria. Var gene transcripts in Papua New Guinean children with severe malaria were similar to those reported from Africa.
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    Correction: Does Malaria Affect Placental Development? Evidence from In Vitro Models
    Umbers, AJ ; Stanisic, DI ; Ome, M ; Wangnapi, R ; Hanieh, S ; Unger, HW ; Robinson, LJ ; Lufele, E ; Baiwog, F ; Siba, PM ; King, CL ; Beeson, JG ; Mueller, I ; Aplin, JD ; Glazier, JD ; Rogerson, SJ ; Hviid, L (Public Library of Science (PLoS), 2013)
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    Malaria prevention in the expatriate and long-term traveller
    O'Brien, D ; Biggs, B (Therapeutic Guidelines Limited, 2002-01-01)
    The prevention of malaria in expatriates and long-term travellers is complex. The traveller's doctor needs to consider the destination, the nature of the travel, the effectiveness and potential adverse effects of antimalarial medication, and the general health of the traveller. A preventative regimen can be devised combining several strategies including mosquito avoidance measures, chemoprophylaxis, emergency standby treatment and rapid self-diagnosis of malaria.
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    Assessment of susceptibility of Plasmodium falciparum to chloroquine, quinine, mefloquine, sulfadoxine-pyrimethamine and artemisinin in southern Viet Nam
    Thanh, NV ; Cowman, AF ; Hipgrave, D ; Kim, TB ; Phuc, BQ ; Cong, LD ; Biggs, BA (ROYAL SOC TROPICAL MEDICINE, 2001)
    Resistance to antimalarial chemotherapy is a major concern for malaria control in Viet Nam. In this study undertaken in 1998, 65 patients with uncomplicated Plasmodium falciparum malaria were monitored for 28 days after completion of a 5-day treatment course with artemisinin. Overall 36.9% (24/65) of patients had recurrent parasitaemia during the surveillance period. P. falciparum isolates were tested for sensitivity in vitro to chloroquine, mefloquine, quinine, sulfadoxine-pyrimethamine and results were compared to those from a similar study in 1995. Increased parasite sensitivity to sulfadoxine-pyrimethamine, chloroquine and quinine was demonstrated, with significantly lower mean EC50 and EC99 values in 1998 compared to 1995. Parasite sensitivity to mefloquine did not differ significantly in the 2 surveys. Isolates were also tested for sensitivity in vitro to artemisinin in the 1998 survey. The mean EC50 was 0.03 mumol/L and the EC99 was 0.94 mumol/L. Parasite sensitivity to artemisinin will need to be monitored in view of its increasing use in Viet Nam.
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    Imported malaria treated in Melbourne, Australia: Epidemiology and clinical features in 246 patients
    Robinson, P ; Jenney, AW ; Tachado, M ; Yung, A ; Manitta, J ; Taylor, K ; Biggs, BA (OXFORD UNIV PRESS INC, 2001)
    BACKGROUND: Imported malaria is increasing in nonendemic countries, including Australia. The objective of this study was to describe the epidemiology and clinical features of travelers with imported malaria presenting to a specialist infectious diseases hospital. METHODS: A retrospective case series of 246 consecutively admitted inpatients with laboratory confirmed malaria. The main outcome measures were the proportion of patients infected with each malaria species, and relationship between species and country of birth, area of acquisition, adequacy of chemoprophylaxis, clinical features, laboratory investigations, and treatment. RESULTS: Plasmodium vivax caused 182 (68.9%) episodes, Plasmodium falciparum caused 71 (26.9%), Plasmodium ovale caused 5 (1.9%), and Plasmodium malariae 1 (0.4%). Fifty-six percent of patients reported chemoprophylaxis use. People born in a country with endemic malaria (36.6%) were less likely to have used chemoprophylaxis. Malaria was most commonly acquired in Papua New Guinea and Southeast Asia. The median times to diagnosis after return to Australia for P. falciparum and P. vivax infections were 1 and 9 weeks respectively. The longest interval between last arrival in Australia and presentation with P. falciparum malaria was 32 weeks. Fever (96%), headache (74%), and a tender or palpable spleen (40%), were the most common clinical features. Diarrhea was more common in P. falciparum, and rigors in P. vivax infections. Thrombocytopenia (71%), abnormal liver function tests and an elevated C-reactive protein (85%) were common. Six patients had severe falciparum malaria but no deaths occurred during the study period. CONCLUSION: Malaria remains a health threat for those traveling in endemic areas and is associated with failure to use chemoprophylaxis appropriately. Nonspecific clinical features may lead to delayed diagnosis and misdiagnosis. Malaria should be suspected in the febrile traveler, regardless of birthplace, prophylaxis, symptomatology, or the time that has elapsed since leaving the malarious area.
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    Chemoprophylaxis and treatment of malaria.
    Rogerson, SJ ; Biggs, BA ; Brown, GV ( 1994-09)
    Prevention of malaria morbidity relies on the use of personal protection from mosquito bites, appropriate chemoprophylactic drugs, and early investigation of symptoms in returning travellers. Malaria chemoprophylaxis must be tailored to the individual patient's travel and personal needs, and no chemoprophylaxis is completely effective. Chloroquine alone is adequate for those areas with P vivax, or sensitive P falciparum but in most circumstances the choice will be between mefloquine and doxycycline. The specific area visited, the time spent there and the individual's medical history will help determine the final choice.
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    Regional differences in the response of Plasmodium vivax malaria to primaquine as anti-relapse therapy
    Goller, JL ; Jolley, D ; Ringwald, P ; Biggs, B-A (AMER SOC TROP MED & HYGIENE, 2007-02)
    We used logistic regression to assess effectiveness of primaquine as Plasmodium vivax anti-relapse therapy using data extracted from studies of P. vivax relapses in Brazil, India, and Thailand. The risk of relapse in Thailand was 10 times that in India and twice that in Brazil. In comparison with no primaquine treatment, the risk of relapse decreased by approximately 80% for a total adult primaquine regimen of 210 mg and by > or =95% for regimens of 315 mg and 420 mg. In addition, we used logistic regression to estimate the risk of P. vivax relapse according to weight-based primaquine dose using data from case studies. There was a three-fold increase in the likelihood of successful treatment of each additional milligram of primaquine per kilogram of body weight. Tailoring primaquine therapy to a region requires consideration of factors including body weight, natural relapse rates, and local response to primaquine.
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    Incomplete Immunity and Missed Vaccination Opportunities in East African Immigrants Settling in Australia
    Skull, SA ; Ngeow, JYY ; Hogg, G ; Biggs, B-A (Springer, 2008-06-01)
    BACKGROUND: Immigrants and refugees are at particular risk of incomplete immunisation and may be unaware of their vaccination status. There is a paucity of data on the immunisation status of adult immigrants from African countries. AIMS: To review the immunisation status of adult immigrants from East Africa, and to identify missed opportunities for vaccination. METHODS: A community survey was conducted using self-reported vaccination status, Mantoux skin tests, and serological testing for immunity to hepatitis B, tetanus, diphtheria and measles. RESULTS: Proven inadequate immunity against at least one of tetanus (67%), hepatitis B (41%), diphtheria (34%) or measles (3%) was found among 100/126 (81%) participants despite a median of seven visits to vaccine providers since immigration. A positive Mantoux test occurred in 17% of participants. CONCLUSIONS: Pre- and post-arrival health assessments are currently failing to address vaccination needs in recently arrived East African adult immigrants. Immigrants should have their immunisation status assessed, with opportunistic vaccination provided wherever possible.
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    The Profile of Health Problems in African Immigrants Attending an Infectious Disease Unit in Melbourne, Australia
    Gibney, KB ; Mihrshahi, S ; Torresi, J ; Marshall, C ; Leder, K ; Biggs, B-A (AMER SOC TROP MED & HYGIENE, 2009-05)
    The number of African immigrants living in Western countries is increasing. A retrospective audit of sub-Saharan African patients attending the infectious diseases clinics of a Melbourne teaching hospital was performed. A total of 375 patients were included. Helicobacter pylori gastritis was diagnosed in 60% of those tested (35/58), schistosomiasis in 41% (84/206), chronic hepatitis B in 19% (32/167), and strongyloidiasis in 18% (32/179). Active tuberculosis (TB) affected 18% (51/276) and latent TB 55% (152/276). Pathologic parasites were detected in stool in 21% (31/145). Vitamin D deficiency (< 50 nmol/L) affected 73% (139/191), anemia 17% (52/312), iron deficiency 15% (22/151), and low neutrophil count 25% (78/312). Infectious diseases, vitamin D deficiency, anemia, and latent TB were common in sub-Saharan African immigrants. Clinicians need to be aware of these conditions to meet the health needs of this group. Comprehensive health checks should be encouraged for new arrivals, particularly from high-risk areas.
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    The effectiveness of 4 monthly albendazole treatment in the reduction of soil-transmitted helminth infections in women of reproductive age in Viet Nam
    Mihrshahi, S ; Casey, GJ ; Montresor, A ; Phuc, TQ ; Thach, DTC ; Tien, NT ; Biggs, B-A (ELSEVIER SCI LTD, 2009-07-15)
    Soil-transmitted helminth (STH) infections are endemic in northern Viet Nam where the climate and agricultural practices, such as the use of human excreta as fertiliser and the use of wastewater for irrigation, favour transmission. An intervention was conducted in Yen Bai Province, north-west Viet Nam, to measure the effectiveness of single dose albendazole (400mg) administered every 4 months for reducing the prevalence of STH infections in women of reproductive age. Stool samples were collected from women before the intervention and 3 and 12 months post-intervention. Information on a range of demographic and socio-economic variables was also collected to measure the major risk factors for high STH burden in this area. The prevalence of hookworm, Ascaris lumbricoides and Trichuris trichiura infection in the baseline sample of 366 women were 76.2%, 19.2% and 29.1%, respectively. In the women who were surveyed at baseline and again at 3 and 12 months after the intervention (n=118) cure rates were 71.3% for hookworm, 87.0% for A. lumbricoides and 81.4% for T. trichiura by the end of the 12 month study period (i.e. after three doses of albendazole). The main risk factor for hookworm infection was if women worked outside (odds ratio (OR)=3.2 (95% Confidence Interval (CI) 1.6-6.2), P=0.001) and the major risk factor for A. lumbricoides and T. trichiura infection was a lack of education. Low educational attainment was also the strongest risk factor for co-infection with all three species of STH (OR=7.5 (95% CI 3.4-16.4), P<0.001). The high rates of hookworm infection in this area of Viet Nam and the high cure rates for all three species of STH with 4 monthly albendazole treatment suggest that this programme should be expanded to all endemic areas in Viet Nam. The study also highlights the important contribution of education to women's health.