Bibliometric Assessment of European and Sub-Saharan African Research Output on Poverty-Related and Neglected Infectious Diseases from 2003 to 2011.

BACKGROUND: The European & Developing Countries Clinical Trials Partnership (EDCTP) is a partnership of European and sub-Saharan African countries that aims to accelerate the development of medical interventions against poverty-related diseases (PRDs). A bibliometric analysis was conducted to 1) measure research output from European and African researchers on PRDs, 2) describe collaboration patterns, and 3) assess the citation impact of clinical research funded by EDCTP. METHODOLOGY/PRINCIPAL FINDINGS: Disease-specific research publications were identified in Thomson Reuters Web of Science using search terms in titles, abstracts and keywords. Publication data, including citation counts, were extracted for 2003-2011. Analyses including output, share of global papers, normalised citation impact (NCI), and geographical distribution are presented. Data are presented as five-year moving averages. European EDCTP member countries accounted for ~33% of global research output in PRDs and sub-Saharan African countries for ~10% (2007-2011). Both regions contributed more to the global research output in malaria (43.4% and 22.2%, respectively). The overall number of PRD papers from sub-Saharan Africa increased markedly (>47%) since 2003, particularly for HIV/AIDS (102%) and tuberculosis (TB) (81%), and principally involving Southern and East Africa. For 2007-2011, European and sub-Saharan African research collaboration on PRDs was highly cited compared with the world average (NCI in brackets): HIV/AIDS 1.62 (NCI: 1.16), TB 2.11 (NCI: 1.06), malaria 1.81 (NCI: 1.22), and neglected infectious diseases 1.34 (NCI: 0.97). The NCI of EDCTP-funded papers for 2003-2011 was exceptionally high for HIV/AIDS (3.24), TB (4.08) and HIV/TB co-infection (5.10) compared with global research benchmarks (1.14, 1.05 and 1.35, respectively). CONCLUSIONS: The volume and citation impact of papers from sub-Saharan Africa has increased since 2003, as has collaborative research between Europe and sub-Saharan Africa. >90% of publications from EDCTP-funded research were published in high-impact journals and are highly cited. These findings corroborate the benefit of collaborative research on PRDs.

Strengthening of the clinical research capacity for malaria: a shared responsibility.

Lack of adequate human resource capacity, good governance, sound physical infrastructure and well-functioning systems impede economic growth in low- and middle-income countries. The heavy burden from disease compounds this. To overcome these setbacks a concerted effort needs to be taken. This requires collective effort of all including the public and private sectors from development partners and from low- and medium-income countries themselves. Specific research capacity gaps, such as lack of expertise and infrastructure to engage in upstream research and development of new products, need to be addressed. Special attention should also be given to those with more acute capacity needs and high disease burden, such as communities in conflict-affected regions. Capacity building approaches need to be innovative and responsive to needs and the ever changing scientific landscape. Therefore, for example, as the global community aims to eliminate and eventually eradicate malaria, there should be an appropriately matched effort to strengthen the capacity to meet these challenges.

Host erythrocyte polymorphisms and exposure to Plasmodium falciparum in Papua New Guinea.

BACKGROUND: The protection afforded by human erythrocyte polymorphisms against the malaria parasite, Plasmodium falciparum, has been proposed to be due to reduced ability of the parasite to invade or develop in erythrocytes. If this were the case, variable levels of parasitaemia and rates of seroconversion to infected-erythrocyte variant surface antigens (VSA) should be seen in different host genotypes. METHODS: To test this hypothesis, P. falciparum parasitaemia and anti-VSA antibody levels were measured in a cohort of 555 asymptomatic children from an area of intense malaria transmission in Papua New Guinea. Linear mixed models were used to investigate the effect of alpha+-thalassaemia, complement receptor-1 and south-east Asian ovalocytosis, as well as glucose-6-phosphate dehydrogenase deficiency and ABO blood group on parasitaemia and age-specific seroconversion to VSA. RESULTS: No host polymorphism showed a significant association with both parasite prevalence/density and age-specific seroconversion to VSA. CONCLUSION: Host erythrocyte polymorphisms commonly found in Papua New Guinea do not effect exposure to blood stage P. falciparum infection. This contrasts with data for sickle cell trait and highlights that the above-mentioned polymorphisms may confer protection against malaria via distinct mechanisms.

Chlamydia trachomatis infection and distribution of serovars in the Eastern Highlands Province, Papua New Guinea.

We have used nested polymerase chain reaction (PCR) and the PCR-based endonuclease digestion method to genotype Chlamydia trachomatis serovars in 460 infected individuals from the Eastern Highlands Province of Papua New Guinea. Our study groups comprised women who presented in labour to the Goroka Base Hospital, their newborn infants, symptomatic children who presented to the hospital's Outpatients Department and men and women from 15 randomly selected villages in the Asaro Valley. In this analysis, the major outer membrane protein (MOMP) gene, omp1, of C. trachomatis was amplified using DNA obtained from the endocervix of women, urine from men, and both the eye and nasopharynx of children. Amplified DNAs were digested concurrently using Alul and a combination of EcoRI, Hinl and Hpall restriction enzymes. The mixtures were separated on electrophoretic gels and the respective serovars designated on the basis of resolved digested DNA patterns. Our results, which were confirmed also by omp1 sequence data, show serovars D, E, F, G, H and L3 to be present in the studied communities. The overall relative frequencies of these serovars were 30%, 21%, 25%, 1%, 20% and 2% respectively, with serovars D, E, F and H accounting for 97% of these infections. Double infections among these principal serovars were also detected in all our study groups but at a low overall frequency of 3%. Serovar D was the major agent involved in the aetiology of chlamydial infection in both children and adults though serovar F was the most frequent in newborn infants. Serovar H was relatively less frequent in symptomatic children. No trachoma-related serovars were detected, confirming the rarity of this disease in Papua New Guinea. In contrast, although clinical cases of lymphogranuloma venereum have not been described in the country, the detection of serovar L3 in this study suggests that it may occur. However, the association of L3 also with childhood infection indicates that it may be causing the same pathology as the serovars D-K that are associated with non-ulcerative sexually transmitted infections.

Skin and hair pigmentation variation in Island Melanesia.

Skin and hair pigmentation are two of the most easily visible examples of human phenotypic variation. Selection-based explanations for pigmentation variation in humans have focused on the relationship between melanin and ultraviolet radiation, which is largely dependent on latitude. In this study, skin and hair pigmentation were measured as the melanin (M) index, using narrow-band reflectance spectroscopy for 1,135 individuals from Island Melanesia. Overall, the results show remarkable pigmentation variation, given the small geographic region surveyed. This variation is discussed in terms of differences between males and females, among islands, and among neighborhoods within those islands. The relationship of pigmentation to age, latitude, and longitude is also examined. We found that male skin pigmentation was significantly darker than females in 5 of 6 islands examined. Hair pigmentation showed a negative, but weak, correlation with age, while skin pigmentation showed a positive, but also weak, correlation with age. Skin and hair pigmentation varied significantly between islands as well as between neighborhoods within those islands. Bougainvilleans showed significantly darker skin than individuals from any other island considered, and are darker than a previously described African-American population. These findings are discussed in relation to prevailing hypotheses about the role of natural selection in shaping pigmentation variation in the human species, as well as the role of demographic processes such as admixture and drift in Island Melanesia.

High prevalence of sexually transmitted infections among female sex workers in the eastern highlands province of Papua New Guinea: correlates and recommendations.

BACKGROUND: More than 200 female sex workers (FSWs) participating in commercial sex along the Highlands Highway of Papua New Guinea were identified in a previous survey. This has implications for the spread of sexually transmitted infections (STIs) and human immunodeficiency virus (HIV) to areas and population groups serviced by the road. GOAL: The goal of this study was to estimate the prevalence of gonorrhea, chlamydia, syphilis, trichomoniasis, and HIV among FSWs in Goroka and Kainantu in the Eastern Highlands Province (EHP) and to identify correlates that could be considered in intervention and control. STUDY: Self-identified FSWs recruited through the Goroka Sex Workers Peer-Mediated Programme were invited to participate. All consenting FSWs underwent pretest counseling and provided sociodemographic and behavioral data using a structured questionnaire. The women were also asked to self-collect vaginal specimens and to provide peripheral blood to detect the respective STIs and HIV. RESULTS: Results were available for 211 FSWs. None of the women were positive for HIV. The overall estimated rates for gonorrhea, chlamydia, syphilis, and trichomoniasis were 21%, 19%, 24%, and 51%, respectively. Seventy-four percent were positive for at least 1 STI and 43% had multiple STI infections. High-risk sexual behaviors were found to be common among the women, including low and inconsistent use of condoms, with most of them attributing this to unavailability, dislike by or familiarity with clients, and being drunk and/or high on marijuana. CONCLUSIONS: STIs are prevalent among FSWs in Goroka and Kainantu in the EHP and are maintained by widespread high-risk sexual behaviors, including low use of condoms. Implications for their spread through the highway warrants increased efforts in intervention. Apart from a need to promote condom acceptance, distribution, and use, other high-risk sexual behavior and correlates identified in this study provide important considerations for intervention and control in this population.

Nitric oxide production and nitric oxide synthase activity in malaria-exposed Papua New Guinean children and adults show longitudinal stability and no association with parasitemia.

Individuals in areas of intense malaria transmission exhibit resistance (or tolerance) to levels of parasitemia in their blood that would normally be associated with febrile illness in malaria-naive subjects. The resulting level of parasitemia associated with illness (the pyrogenic threshold) is highest in childhood and lowest in adulthood. Clinical parallels between malarial and bacterial endotoxin tolerance have led to the supposition that both share common physiological processes, with nitric oxide (NO) proposed as a candidate mediator. The hypotheses that NO mediates tolerance and blood stage parasite killing in vivo were tested by determining its relationship to age and parasitemia cross-sectionally and longitudinally in a population of 195 children and adults from Papua New Guinea encountering intense malaria exposure. Despite pharmacological clearance of asymptomatic parasitemia, NO production and mononuclear cell NO synthase (NOS) activity were remarkably stable within individuals over time, were not influenced by parasitemia, and varied little with age. These results contrast with previous smaller cross-sectional studies. Baseline NO production and NOS activity did not protect against recurrent parasitemia, consistent with previous data suggesting that NO does not have antiparasitic effects against blood stage infection in vivo. The NO indices studied were markedly higher in specimens from study subjects than in samples from Australian controls, and NOS activity was significantly associated with plasma immunoglobulin E levels, consistent with induction of NO by chronic exposure to other infections and/or host genetic factors. These results suggest that NO is unlikely to mediate killing of blood stage parasites in this setting and is unlikely to be the primary mediator in the acquisition or maintenance of malarial tolerance.

Glycophorin C (Gerbich antigen blood group) and band 3 polymorphisms in two malaria holoendemic regions of Papua New Guinea.

The geographic overlap between the prevalence of erythrocyte polymorphisms and malaria endemicity is thought to be an example of natural selection on human populations. In Papua New Guinea (PNG), the Gerbich-negative phenotype is caused by an exon 3 deletion in the glycophorin C gene (GYPCDeltaex3) while heterozygosity for a 27-base pair deletion in the SLC4A1 gene (anion exchanger 1 or erythrocyte membrane protein, band 3), SLC4A1Delta27, results in Southeast Asian ovalocytosis. Two geographically and ethnically distinct malaria endemic regions of PNG (the Wosera [East Sepik Province] and Liksul [Madang Province]) were studied to illustrate the distribution of two prominent deletion polymorphisms (GYPCDeltaex3 and SLC4A1Delta27) and to determine if the genetic load associated with SLC4A1Delta27 would constrain independent assortment of GYPCDeltaex3 heterozygous and homozygous genotypes. The frequency of the GYPCDeltaex3 allele was higher in the Wosera (0.463) than Liksul (0.176) (chi(2); P < 0.0001). Conversely, the frequency of the SLC4A1Delta27 allele was higher in Liksul (0.0740) than the Wosera (0.0005) (chi(2); P < 0.0001). No individuals were homozygous for SLC4A1Delta27. In 355 Liksul residents, independent assortment of these two deletion polymorphisms resulted in 14 SLC4A1Delta27 carriers heterozygous for GYPCDeltaex3 and one SLC4A1Delta27 carrier homozygous for GYPCDeltaex3 (Fisher's exact test; P = 0.8040). While homozygosity for SLC4A1Delta27 appears to be nonviable, the GYPCDeltaex3 allele is not lethal when combined with SLC4A1Delta27. Neither mutation was associated with altered susceptibility to asymptomatic Plasmodium falciparum or P. vivax infection. While these erythrocyte polymorphisms apparently have no effect on blood-stage malaria infection, their contribution to susceptibility to clinical malaria morbidity requires further study.

Plasma interleukin-12 in malaria-tolerant papua new guineans: inverse correlation with Plasmodium falciparum parasitemia and peripheral blood mononuclear cell nitric oxide synthase activity.

Interleukin-12 (IL-12) has been inversely associated with disease severity in human and murine malaria, and a polymorphism in the IL-12 p40 subunit gene (IL12B) has been associated with susceptibility to human cerebral malaria and reduced nitric oxide (NO) production. To better define the relationships between IL-12, NO, malaria parasitemia, and IL12B polymorphisms during malarial tolerance, plasma IL-12 levels and peripheral blood mononuclear cell NO synthase (NOS) activity were measured in asymptomatic Papua New Guineans exposed to intense malaria transmission. The IL-12 level was strongly inversely correlated with the density of Plasmodium falciparum parasitemia (rho = -0.45; P < 0.001) and was predicted to decrease by 19% (95% confidence interval [CI], 10 to 27%) for each twofold increase in P. falciparum parasitemia. This is consistent with a suppressive effect of parasitemia on IL-12 production, an effect previously shown in vitro and in rodent models of disease. The IL-12 level was inversely correlated with NOS activity (r = -0.22; P = 0.007), with each twofold increase in NOS activity being predictive of a 25% (95% CI, 7 to 38%) decrease in plasma IL-12 levels. This probably reflects additional down-regulation of IL-12 by the high basal NO production and monocyte NOS expression found in the malaria-tolerant state. Neither the IL-12 level nor NOS activity was associated with either of two IL12B polymorphisms, reflecting the diversity of genetic control over immune responses in different populations.

Clinical presentation of subacute sclerosing panencephalitis in Papua New Guinea.

Eighty-three children presented at Goroka Base Hospital in the Eastern Highlands Province (EHP) of Papua New Guinea over a period of 3 years and 9 months between February 1997 and November 2000 were confirmed to have subacute sclerosing panencephalitis (SSPE). Confirmation of the diagnosis was based on the demonstration of high titres of measles antibodies in the cerebrospinal fluid and/or serum in association with clinical features supportive of SSPE, including characteristic electroencephalographic changes and amplification of measles virus genome by reverse transcriptase polymerase chain reaction in some cases. The mean cerebrospinal fluid and serum enzyme immunoassay antibody levels among the SSPE patients were 38 250 and 860 580, respectively. The mean age of onset of SSPE was 7.9 +/- 2.6 years and ranged between 2 and 14 years. The overall male to female ratio was 1.2:1 and 1.4:1 for EHP.

Measles: not just another viral exanthem.

Measles is the most frequent cause of vaccine-preventable childhood deaths. Infants younger than the recommended age for vaccination are susceptible to the disease, and in developing countries they have a high risk of complications and mortality. Vaccine coverage in excess of 95% interrupts endemic transmission of measles in many countries, but achievement of such coverage almost always requires coordinated supplementary mass vaccination campaigns. There are substantial health gains if countries improve measles vaccine coverage, irrespective of whether or not high coverage is achieved; these gains include much lower measles complication and case fatality rates, long-term interepidemic duration, and possibly non-specific improvements in survival of children. Investigation into the cost-effectiveness of different strategies for measles control, including mass campaigns, two-dose schedules, and young-infant doses, would help countries to formulate control policies appropriate to their setting. Pneumonia is the most common fatal complication associated with measles, and at least 50% of measles-related pneumonias are due to bacterial superinfection. WHO has developed standard case management programmes for measles, but there are several unresolved clinical issues, including optimum indications for antibiotic treatment, the importance of intravenous immunoglobulin, the role of viral coinfection, and the risk of tuberculosis after measles. The priority in worldwide efforts to control measles is to lend support to poor countries, helping them to increase vaccine coverage and sustain improvements to vaccination infrastructure, and to address technical issues with respect to optimum vaccination schedules. Measles represents a specific challenge, whereby partnerships between high-income and developing nations would reduce child mortality in developing countries; such partnerships are not without incentive for high-income countries, since without them imported measles cannot be prevented.

Immunoglobulin G (IgG) responses to Plasmodium falciparum glycosylphosphatidylinositols are short-lived and predominantly of the IgG3 subclass.

The induction of neutralizing immunity to Plasmodium falciparum toxins by vaccination has been proposed as a preventive strategy to limit the severity of malaria. For this approach to be successful, generation of a sustained immune response would be necessary. This study shows that immunoglobulin G (IgG)-subclass responses elicited by the proposed P. falciparum toxin glycosylphosphatidylinositol (GPI) in Papua New Guinean subjects 5-60 years old predominantly involve IgG(3), with a lesser contribution from IgG(1) and an absence of IgG(2) and IgG(4). IgG(3) levels declined sharply within 6 weeks of pharmacological clearance of parasitemia in all subjects, whereas a significant decrease in IgG(1) levels was seen only in subjects < or =19 years old. Because the natural antibody response to P. falciparum GPIs is skewed toward the short-lived IgG(3) subclass, a vaccination strategy with GPI analogues would likely require augmentation by costimulatory molecules, to induce a more persistent anti-GPI response.

Inducible nitric oxide synthase (NOS2) promoter CCTTT repeat polymorphism: relationship to in vivo nitric oxide production/NOS activity in an asymptomatic malaria-endemic population.

Polymorphisms in the inducible nitric oxide synthase gene (NOS2) promoter have been associated with clinical outcome from malaria. These include a CCTTT repeat (CCTTTn) 2.5 kilobases upstream from the NOS2 transcription start site, and two single nucleotide substitutions: G-->C at position -954 (G-954C), and C-->T at position -1173 (C-1173T). Although hypothesized to influence NO production in vivo, the functional relevance of (CCTTT)n and G-954C is uncertain because disease association studies have yielded inconsistent results. This study found no association between CCTTT repeat number and levels of plasma NO metabolites or peripheral blood mononuclear cell NOS activity in a cohort of asymptomatic malaria-exposed coastal Papua New Guineans 1-60 years old. This suggests that (CCTTT)n does not independently influence NOS2 transcription in vivo. Neither the G-954C nor the C-1173T polymorphisms were identified in this population, indicating the variability and complexity of selection for NOS2 promoter polymorphisms in different malaria-endemic populations.

High prevalence of Neisseria gonorrhoeae and multiple sexually transmitted diseases among rural women in the Eastern Highlands Province of Papua New Guinea, detected by polymerase chain reaction.

BACKGROUND: In a previous community-based study among rural women in the Eastern Highlands Province (EHP) of Papua New Guinea we determined that the prevalences of Trichomonas vaginalis infection, Chlamydia trachomatis infection, and syphilis were 46%, 26%, and 4%, respectively. Surprisingly, however, the prevalence of Neisseria gonorrhoeae infection was only 1%, which we considered low in consideration of the high prevalence of other sexually transmitted diseases (STDs). The aim of the current study was to reexamine samples that were collected in that survey and retest them with use of polymerase chain reaction (PCR). STUDY DESIGN: Using a cluster-sampling method, we surveyed 201 women aged 15 to 45 years in a population of approximately 19,000 people. In addition, 243 other women living in the same area who wished to be screened for STDs were included in the study. METHODS: Endocervical samples that were stored frozen at -80 degrees C were retested with multiplex PCR (M-PCR) for the detection of both N gonorrhoeae and C trachomatis and with a separate PCR for the detection of T vaginalis. RESULTS: A total of 373 samples that were still available were analyzed. The prevalences of T vaginalis, C trachomatis, and N gonorrhoeae infections were 42.6%, 26.5%, and 18.2%, respectively; 59.8% of the women had at least one STD, while 21.7% had mixed infections, 5.9% of them with all three pathogens. CONCLUSIONS: STDs are very common among rural women in the EHP of Papua New Guinea and often present as multiple infections.

Molecular analysis of measles virus genome derived from SSPE and acute measles patients in Papua, New Guinea.

A very high annual incidence of 56 per million population below the age of 20 years for subacute sclerosing panencephalitis (SSPE) has been reported from Papua New Guinea (PNG). In a more recent study, we have confirmed this unusual high incidence for Eastern Highlands Province (EHP) of PNG. In the study, it was observed that the vaccination rate among SSPE patients registered at Goroka Base General Hospital (GBGH) in EHP was higher than that of other infants in the province in recent years. To identify the measles virus (MV) responsible for SSPE in EHP, sequence analysis of hypervariable region of the N gene was performed from 13 MV genomes: 2 amplified from clinical specimens of SSPE patients and 11 from acute measles patients. In 2 cases among the 11 with acute measles, nucleotide sequence of the entire H gene derived from isolated viruses was determined. Both nucleotide sequence and phylogenetic tree analyses showed that the amplified MV cDNAs were closely related to one another and belonged to the D3 genotype though they were different from any previously reported MV sequences. No genome sequences of vaccine strains were detected. These findings suggest that the MV strains prevailing in the highlands of PNG belong to genotype D3 of the MV and this wild-type MV rather than the vaccine strains was likely to be responsible for SSPE in these patients.

JC virus genotypes in the western Pacific suggest Asian mainland relationships and virus association with early population movements.

Distinct genotypes of human polyomavirus JC (JCV) have remained population associated possibly from the time of dispersal of modern humans from Africa. Seven major genotypes with additional subtypes serve as plausible markers for following early and more recent human migrations in all parts of the world. Phylogenetic trees of JCV sequences from the major continental population groups show a trifurcation at the base indicating early division into European, African, and Asian branches. Here, we have explored JCV relationships in the island populations of the western Pacific. Since these islands were settled from the Asian mainland and islands of Southeast Asia, we expected that their virus genotypes might show an Asian connection. We found that Type 2E (Austronesian) and Type 8 (non-Austronesian) are widely distributed in western Pacific populations. A few south China strains were found (Type 7A). A subtype of Type 8, Type 8A, was confined to Papua New Guinea. In keeping with these assignments we find that phylogenetic analysis by neighbor-joining and maximum parsimony methods places Type 2E in a closer relationship to east Asian mainland strains such as Type 2A and Type 7. Our findings support the Asian origins of the western Pacific JCV strains, and suggest three broad movements: an ancient one characterized by Type 8A, and then Type 8B, followed much later by migrations carrying Type 2E, which may correlate with the arrival of Austronesian-language speakers, the bearers of the "Lapita" cultural complex (approximately 3,500 to 5,000 years ago), and relatively recent movements carrying largely Type 7A (south China) strains directly from the West.