Mitja O.,University of Barcelona |
Mitja O.,Lihir Medical Center International |
Lukehart S.A.,University of Washington |
Pokowas G.,Lihir Medical Center International |
And 9 more authors.
The Lancet Global Health | Year: 2014
Background: Skin infections with ulceration are a major health problem in countries of the south Pacific region. Yaws, caused by Treponema pallidum subspecies pertenue and diagnosed by the presence of skin ulcers and a reactive syphilis serology, is one major cause, but this infection can be confused clinically with ulcers due to other causative agents. We investigated T pallidum pertenue and another bacterium known to cause skin infections in the Pacific islands. Haemophilus ducreyi-as causes of skin ulceration in a yaws-endemic region. Additionally, we identified specific signs and symptoms associated with these causative agents of cutaneous ulcers and compared these findings with laboratory-based diagnoses. Methods: We did a prospective cohort study of five yaws-endemic villages (total population 3117 people) during a yaws elimination campaign in Papua New Guinea in April, 2013. We enrolled all consenting patients with chronic moist or exudative skin ulcers. We undertook a detailed dermatological assessment, syphilis serology, and PCR on lesional swabs to detect the presence of T pallidum pertenue and H ducreyi. Patients with PCR-confirmed bacterial infections were included in a comparative analysis of demographics and clinical features. Findings: Full outcome data were available for 90 people with skin ulcers. Of these patients, 17 (19%) had negative results in all molecular tests and were therefore excluded from the comparative analyses. A bacterial cause was identified in 73 (81%) participants-either H ducreyi (n=42), T pallidum pertenue (yaws; n=19), or coinfection with both organisms (dual infection; n=12). The demographic characteristics of the patients infected with yaws and with H ducreyi were similar. Skin lesions in patients with yaws and in those with dual infection were larger than those in patients infected with H ducreyi (p=0·071). The lesions in patients with yaws and dual infection were more circular in shape (79% and 67%) than in those infected with H ducreyi (21%; p<0·0001); more likely to have central granulating tissue (90% and 67% vs 14%; p<0·0001); and more likely to have indurated edges (74% and 83% vs 31%; p=0·0003). The prevalence of reactive combined serology (positive T pallidum haemagglutination test and rapid plasmin reagin titre of ≥1:8) was higher in cases of yaws (63%) and dual infections (92%) than in H ducreyi infections (29%; p<0·0001). Interpretation: In this yaws-endemic community, H ducreyi is an important and previously unrecognised cause of chronic skin ulceration. Reactive syphilis serology caused by latent yaws can occur in ulcers with the presence of H ducreyi alone. The introduction of PCR for ulcer surveillance could improve the accuracy of diagnosis in countries with yaws eradication campaigns. © 2014 Mitjà et al.
Parola P.,Aix - Marseille University |
Paddock C.D.,Centers for Disease Control and Prevention |
Socolovschi C.,Aix - Marseille University |
Labruna M.B.,University of Sao Paulo |
And 8 more authors.
Clinical Microbiology Reviews | Year: 2013
Tick-borne rickettsioses are caused by obligate intracellular bacteria belonging to the spotted fever group of the genus Rickettsia. These zoonoses are among the oldest known vector-borne diseases. However, in the past 25 years, the scope and importance of the recognized tick-associated rickettsial pathogens have increased dramatically, making this complex of diseases an ideal paradigm for the understanding of emerging and reemerging infections. Several species of tick-borne rickettsiae that were considered nonpathogenic for decades are now associated with human infections, and novel Rickettsia species of undetermined pathogenicity continue to be detected in or isolated from ticks around the world. This remarkable expansion of information has been driven largely by the use of molecular techniques that have facilitated the identification of novel and previously recognized rickettsiae in ticks. New approaches, such as swabbing of eschars to obtain material to be tested by PCR, have emerged in recent years and have played a role in describing emerging tick-borne rickettsioses. Here, we present the current knowledge on tick-borne rickettsiae and rickettsioses using a geographic approach toward the epidemiology of these diseases. © 2013, American Society for Microbiology. All Rights Reserved.
Martinez I.,University of Alberta |
Martinez I.,University of Nebraska - Lincoln |
Stegen J.C.,Pacific Northwest National Laboratory |
Maldonado-Gomez M.X.,University of Nebraska - Lincoln |
And 6 more authors.
Cell Reports | Year: 2015
Although recent research revealed an impact of westernization on diversity and composition of the human gut microbiota, the exact consequences on metacommunity characteristics are insufficiently understood, and the underlying ecological mechanisms have not been elucidated. Here, we have compared the fecal microbiota of adults from two non-industrialized regions in Papua New Guinea (PNG) with that of United States (US) residents. Papua New Guineans harbor communities with greater bacterial diversity, lower inter-individual variation, vastly different abundance profiles, and bacterial lineages undetectable in US residents. A quantification of the ecological processes that govern community assembly identified bacterial dispersal as the dominant process that shapes the microbiome in PNG but not in the US. These findings suggest that the microbiome alterations detected in industrialized societies might arise from modern lifestyle factors limiting bacterial dispersal, which has implications for human health and the development of strategies aimed to redress the impact of westernization. © 2015 The Authors.
Asante E.A.,University College London |
Smidak M.,University College London |
Grimshaw A.,University College London |
Houghton R.,University College London |
And 15 more authors.
Nature | Year: 2015
Mammalian prions, transmissible agents causing lethal neurodegenerative diseases, are composed of assemblies of misfolded cellular prion protein (PrP). A novel PrP variant, G127V, was under positive evolutionary selection during the epidemic of kuru - an acquired prion disease epidemic of the Fore population in Papua New Guinea - and appeared to provide strong protection against disease in the heterozygous state. Here we have investigated the protective role of this variant and its interaction with the common, worldwide M129V PrP polymorphism. V127 was seen exclusively on a M129 PRNP allele. We demonstrate that transgenic mice expressing both variant and wild-type human PrP are completely resistant to both kuru and classical Creutzfeldt-Jakob disease (CJD) prions (which are closely similar) but can be infected with variant CJD prions, a human prion strain resulting from exposure to bovine spongiform encephalopathy prions to which the Fore were not exposed. Notably, mice expressing only PrP V127 were completely resistant to all prion strains, demonstrating a different molecular mechanism to M129V, which provides its relative protection against classical CJD and kuru in the heterozygous state. Indeed, this single amino acid substitution (G-V) at a residue invariant in vertebrate evolution is as protective as deletion of the protein. Further study in transgenic mice expressing different ratios of variant and wild-type PrP indicates that not only is PrP V127 completely refractory to prion conversion but acts as a potent dose-dependent inhibitor of wild-type prion propagation. © 2015 Macmillan Publishers Limited. All rights reserved.
van den Biggelaar A.H.J.,University of Western Australia |
Pomat W.S.,Papua New Guinea Institute of Medical Research
Vaccine | Year: 2013
Bacterial conjugate vaccines are based on the principle of coupling immunogenic bacterial capsular polysaccharides to a carrier protein to facilitate the induction of memory T-cell responses. Following the success of Haemophilus influenzae type b conjugate vaccines in the 1980s, conjugate vaccines for Streptococcus pneumoniae and Neisseria meningitidis infections were developed and proven to be effective in protecting children against invasive disease. In this review, the use of conjugate vaccines in human newborns is discussed. Neonatal Haemophilus influenzae type b and pneumococcal conjugate vaccination schedules have been trialed and proven to be safe, with the majority of studies demonstrating no evidence for the induction of immune tolerance. Whether their neonatal administration also results in an earlier induction of clinical protection in the first 2-3 critical months of life is still to be demonstrated. © 2012 Elsevier Ltd.
Davis T.M.E.,University of Western Australia |
Mueller I.,Papua New Guinea Institute of Medical Research |
Rogerson S.J.,University of Melbourne
Future Microbiology | Year: 2010
Malaria in pregnancy is a substantial public health issue in many tropical countries. However, its prevention and treatment have been hindered because of fears of adverse drug effects in pregnant women recruited to intervention studies. This article details the pharmacological agents and management strategies currently or potentially available for use in pregnant women with or at risk of malaria. There are deficiencies in pharmacokinetic, tolerability, safety and efficacy data for even well-established drugs and combinations. This can have serious implications for the design of rational dose regimens. Approaches such as intermittent preventive treatment are increasingly employed in endemic areas with proven benefits, but the emergence of parasite drug resistance means that new strategies and drug regimens should be continually evaluated. © 2010 Future Medicine Ltd.
Wong R.P.M.,University of Western Australia |
Salman S.,University of Western Australia |
Ilett K.F.,University of Western Australia |
Siba P.M.,Papua New Guinea Institute of Medical Research |
And 2 more authors.
Antimicrobial Agents and Chemotherapy | Year: 2011
Desbutyl-lumefantrine (DBL) is a metabolite of lumefantrine. Preliminary data from Plasmodium falciparum field isolates show greater antimalarial potency than, and synergy with, the parent compound and synergy with artemisinin. In the present study, the in vitro activity and interactions of DBL were assessed from tritium-labeled hypoxanthine uptake in cultures of the laboratory-adapted strains 3D7 (chloroquine sensitive) and W2mef (chloroquine resistant). The geometric mean 50% inhibitory concentrations (IC50s) for DBL against 3D7 and W2mef were 9.0 nM (95% confidence interval, 5.7 to 14.4 nM) and 9.5 nM (95% confidence interval, 7.5 to 11.9 nM), respectively, and those for lumefantrine were 65.2 nM (95% confidence interval, 42.3 to 100.8 nM) and 55.5 nM (95% confidence interval, 40.6 to 75.7 nM), respectively. An isobolographic analysis of DBL and lumefantrine combinations showed no interaction in either laboratory-adapted strain but mild synergy between DBL and dihydroartemisinin (sums of the fractional inhibitory concentrations of 0.92 [95% confidence interval, 0.87 to 0.98] and 0.94 [95% confidence interval, 0.90 to 0.99] for 3D7 and W2mef, respectively). Using a validated ultra-high-performance liquid chromatography-tandem mass spectrometry assay and 94 day 7 samples from a previously reported intervention trial, the mean plasma DBL was 31.9 nM (range, 1.3 to 123.1 nM). Mean plasma DBL concentrations were lower in children who failed artemether-lumefantrine treatment than in those with an adequate clinical and parasitological response (ACPR) (P = 0.053 versus P > 0.22 for plasma lumefantrine and the plasma lumefantrine-to-DBL ratio, respectively). DBL is more potent than the parent compound and mildly synergistic with dihydroartemisinin. These properties and the relationship between day 7 plasma concentrations and the ACPR suggest that it could be a useful alternative to lumefantrine as a part of artemisinin combination therapy. Copyright © 2011, American Society for Microbiology. All Rights Reserved.
Maraga S.,Papua New Guinea Institute of Medical Research
Papua and New Guinea medical journal | Year: 2011
As the last part of a program to survey the extent of malaria transmission in the Papua New Guinea highlands, a series of rapid malaria surveys were conducted in 2003-2004 and 2005 in different parts of Southern Highlands Province. Malaria was found to be highly endemic in Lake Kutubu (prevalence rate (PR): 17-33%), moderate to highly endemic in Erave (PR: 10-31%) and moderately endemic in low-lying parts (< 1500 m) of Poroma and Kagua (PR: 12-17%), but was rare or absent elsewhere. A reported malaria epidemic prior to the 2004 surveys could be confirmed for the Poroma (PR: 26%) but not for the lower Kagua area. In Kutubu/Erave Plasmodium falciparum was the most common cause of infection (42%), followed by P. vivax (39%) and P. malariae (16%). In other areas most infections were due to P. vivax (63%). Most infections were of low density (72% < 500/ microl) and not associated with febrile illness. Overall, malaria was only a significant source of febrile illness when prevalence rates rose above 10%, or in epidemics. However, concurrent parasitaemia led to a significant reduction in haemoglobin (Hb) level (1.2 g/dl, CI95: [1.1-1.4.], p < 0.001) and population mean Hb levels were strongly correlated with overall prevalence of malarial infections (r = -0.79, p < 0.001). Based on the survey results, areas of different malaria epidemiology are delineated and options for control in each area are discussed.
Phuanukoonnon S.,Papua New Guinea Institute of Medical Research
Papua and New Guinea medical journal | Year: 2010
Infants in Papua New Guinea (PNG) are at a high risk of invasive pneumococcal disease, and a substantial burden of this falls on children less than six months old. PNG is planning to introduce a pneumococcal conjugate vaccine for infants in the near future, but to make the maximum impact neonatal immunization will have to be considered. To provide evidence on safety and immunogenicity for neonatal and early infant immunization, we undertook an open randomized controlled trial of 7-valent pneumococcal conjugate vaccine (7vPCV). 318 children received 7vPCV at ages 0, 1 and 2 months or at 1, 2 and 3 months or not at all. All children received 23-valent pneumococcal polysaccharide vaccine at age 9 months. This was a large and complex trial: village reporters visited participants weekly during the first year and fortnightly for a further 6 months and nurses monitored self-reported morbidity and collected many thousands of biological samples. The study team was remarkably successful in achieving the study aims, with 18-month follow-up completed on 77% of enrolled children and over 80% of scheduled samples collected. While the results of the trial will be reported elsewhere, this paper discusses the design of the study and dissects out some of the main reasons for its successful completion. Strong community engagement was an essential factor in success and the principles of equitable partnership and service provision led to a strong research partnership. A two-stage consent process, comprising primary assent followed by later informed consent, led to a high drop-out before initial enrolment, but an outstanding retention of those enrolled in the study. We conclude that factors such as strong community participation, reciprocity and a good relationship between the study team and participants are just as important as the technical elements of laboratory testing and data handling in ensuring the success of a vaccine trial in PNG.
Kelly A.,Papua New Guinea Institute of Medical Research
Papua and New Guinea medical journal | Year: 2011
The relationship between HIV (human immunodeficiency virus), food security and nutrition has become increasingly important to practitioners, policy makers and people living with HIV. In this paper we describe for the first time the connection between HIV and antiretroviral therapies, the extent of nutritional counselling for HIV-positive people and food security in Papua New Guinea (PNG). A total of 374 HIV-positive people who were over the age of 16 and who had been on antiretroviral therapy (ART) for more than two weeks were recruited from six provinces, using a non-probability, convenience sampling methodology. A subsample of 36 participants also completed an in-depth qualitative interview. Participants received nutritional advice when beginning ART which focused on three main domains, of which the first two were the most frequently mentioned: what foods to avoid; what foods to eat; and how frequently to eat. 72% of the sample reported that they had experienced an increase in their appetite. Of those who reported that their appetite had increased on ART 33% reported that they did not have enough food to satisfy hunger. People who lived in the capital city, Port Moresby, within the Southern Region of PNG, had significantly more difficulty with food security than those who lived in other regions of the country. Not having enough food was the third most commonly recorded reason for non-adherence to ART. Responses to the HIV epidemic in Papua New Guinea must also begin to address the phenomenon of food insecurity for people with HIV, in particular those who are receiving antiretroviral therapies and who live in the urban areas.