Efforts to monitor malaria transmission increasingly use cross-sectional surveys to estimate transmission intensity from seroprevalence data using malarial antibodies. To date, seroconversion rates estimated from cross-sectional surveys have not been compared to rates estimated in prospective cohorts. Our objective was to compare seroconversion rates estimated in a prospective cohort with those from a cross-sectional survey in a low-transmission population.

Obstetric fistula is a serious medical condition which affects women in low income countries. Despite the progress of research on fistula, there is little data on long term follow-up after surgical repair. The objective of this study is to analyse the factors associated with the recurrence of fistula and the outcomes of pregnancy following fistula repair in Guinea.

To date there are no approved antiviral drugs for the treatment of Ebola virus disease (EVD). Based on our in vitro evidence of antiviral activity of interferon (IFN)-ß activity against Ebola virus, we conducted a single arm clinical study in Guinea to evaluate the safety and therapeutic efficacy of IFN β-1a treatment for EVD. Nine individuals infected with Ebola virus were treated with IFN β-1a and compared retrospectively with a matched cohort of 21 infected patients receiving standardized supportive care only during the same time period at the same treatment unit. Cognizant of the limitations of having treated only 9 individuals with EVD, the data collected are cautiously considered. When compared to supportive care only, IFN β-1a treatment seemed to facilitate viral clearance from the blood and appeared associated with earlier resolution of disease symptoms. Survival, calculated from the date of consent for those in the trial and date of admission from those in the control cohort, to the date of death, was 19% for those receiving supportive care only, compared to 67% for those receiving supportive care plus IFN β-1a. Given the differences in baseline blood viremia between the control cohort and the IFN-treated cohort, an additional 17 controls were included for a subset analysis, from other treatment units in Guinea, matched with the IFN-treated patients based on age and baseline blood viremia. Subset analyses using this expanded control cohort suggests that patients without IFN β-1a treatment were ~ 1.5-1.9 fold more likely to die than those treated. Viewed altogether the results suggest a rationale for further clinical evaluation of IFN β-1a.

Serological antibody levels are a sensitive marker of pathogen exposure, and advances in multiplex assays have created enormous potential for large-scale, integrated infectious disease surveillance. Most methods to analyze antibody measurements reduce quantitative antibody levels to seropositive and seronegative groups, but this can be difficult for many pathogens and may provide lower resolution information than quantitative levels. Analysis methods have predominantly maintained a single disease focus, yet integrated surveillance platforms would benefit from methodologies that work across diverse pathogens included in multiplex assays.

Pediculus humanus capitis, the head louse, is an obligate blood-sucking ectoparasite that occurs in six divergent mitochondrial clades (A, D, B, F, C and E). Several studies reported the presence of different pathogenic agents in head lice specimens collected worldwide. These findings suggest that head louse could be a dangerous vector and a serious public health problem. Herein, we aimed to study the mitochondrial genetic diversity, the PHUM540560 gene polymorphisms profile of head lice collected in Guinea, as well as to screen for their associated pathogens. In 2018, a total of 155 head lice were collected from 49 individuals at the Medicals Centers of rural (Maférinyah village) and urban (Kindia city) areas, in Guinea. Specimens were subjected to a genetic analysis and pathogens screening using molecular tools. Results showed that all head lice belonged to eight haplotypes in the E haplogroup, with six newly identified for the first time. The study of the PHUM540560 gene polymorphisms of our clade E-head lice revealed that 82.5% exhibited the same polymorphism profile as the previously reported clade A-body lice. Screening for targeted pathogens revealed the presence of Acinetobacter spp., while sequencing highlighted the presence of several species, including Acinetobacter baumannii, Acinetobacter nosocomialis, Acinetobacter variabilis, Acinetobacter towneri and for the first time Acinetobacter haemolyticus. Our study is the first to report the existence of the Guinean haplogroup E, the PHUM540560 gene polymorphism profile as well as the presence of Acinetobacter species in head lice collected from Guinea.

Since the adoption of free obstetric care policy in Guinea in 2011, no study has examined the surgical site infections in maternity facilities. The objective of this study was to assess the trends of and factors associated with surgical site infection following cesarean section in Guinean maternity facilities from 2013 to 2015. This was a retrospective cohort study using routine medical data from ten facilities. Overall, the incidence of surgical site infections following cesarean section showed a declining trend across the three periods (10% in 2013, 7% in 2014 and 5% in 2015, P<0.001). Women who underwent cesarean section in 2014 (AOR: 0.70; 95%CI: 0.57-0.84) and 2015 (AOR: 0.43; 95%CI: 0.34-0.55) were less likely to develop surgical site infections during hospital stay than women operated in 2013. In the contrary, women with comorbidities were more likely to experience surgical site infection (AOR: 1.54; 95% CI: 1.25-1.90) than those who did not have comorbidities. The reductions achieved in 2014 and 2015 (during the Ebola outbreak) should be sustained in the post-Ebola context.

The spread of drug resistance to antimalarial treatments poses a serious public health risk globally. To combat this risk, molecular surveillance of drug resistance is imperative. We report the prevalence of mutations in the Plasmodium falciparum kelch 13 propeller domain associated with partial artemisinin resistance, which we determined by using Sanger sequencing samples from patients enrolled in therapeutic efficacy studies from 9 sub-Saharan countries during 2014-2018. Of the 2,865 samples successfully sequenced before treatment (day of enrollment) and on the day of treatment failure, 29 (1.0%) samples contained 11 unique nonsynonymous mutations and 83 (2.9%) samples contained 27 unique synonymous mutations. Two samples from Kenya contained the S522C mutation, which has been associated with delayed parasite clearance; however, no samples contained validated or candidate artemisinin-resistance mutations.

Plasmodium falciparum resistance to artemisinin has emerged in the Greater Mekong Subregion and now poses a threat to malaria control and prevention. Recent work has identified mutations in the kelch propeller domain of the P. falciparum K13 gene to be associated artemisinin resistance as defined by delayed parasite clearance and ex vivo ring stage survival assays. Species specific primers for the two most prevalent human malaria species, P. falciparum and P. vivax, were designed and tested on multiple parasite isolates including human, rodent, and non- humans primate Plasmodium species. The new protocol described here using the species specific primers only amplified their respective species, P. falciparum and P. vivax, and did not cross react with any of the other human malaria Plasmodium species. We provide an improved species specific PCR and sequencing protocol that could be effectively used in areas where both P. falciparum and P. vivax are circulating. To design this improved protocol, the kelch gene was analyzed and compared among different species of Plasmodium. The kelch propeller domain was found to be highly conserved across the mammalian Plasmodium species.

Collection of surveillance data is essential for monitoring and evaluation of public health programs. Integrated collection of household-based health data, now routinely carried out in many countries through demographic health surveys and multiple indicator surveys, provides critical measures of progress in health delivery. In contrast, biomarker surveys typically focus on single or related measures of malaria infection, HIV status, vaccination coverage, or immunity status for vaccine-preventable diseases (VPD). Here we describe an integrated biomarker survey based on use of a multiplex bead assay (MBA) to simultaneously measure antibody responses to multiple parasitic diseases of public health importance as part of a VPD serological survey in Cambodia. A nationally-representative cluster-based survey was used to collect serum samples from women of child-bearing age. Samples were tested by MBA for immunoglobulin G antibodies recognizing recombinant antigens from Plasmodium falciparum and P. vivax, Wuchereria bancrofti, Toxoplasma gondii, Taenia solium, and Strongyloides stercoralis. Serologic IgG antibody results were useful both for generating national prevalence estimates for the parasitic diseases of interest and for confirming the highly focal distributions of some of these infections. Integrated surveys offer an opportunity to systematically assess the status of multiple public health programs and measure progress toward Millennium Development Goals.

The recent emergence of artemisinin resistance in the Greater Mekong Subregion poses a major threat to the global effort to control malaria. Tracking the spread and evolution of artemisinin-resistant parasites is critical in aiding efforts to contain the spread of resistance. A total of 417 patient samples from the year 2007, collected during malaria surveillance studies across ten provinces in Thailand, were genotyped for the candidate Plasmodium falciparum molecular marker of artemisinin resistance K13. Parasite genotypes were examined for K13 propeller mutations associated with artemisinin resistance, signatures of positive selection, and for evidence of whether artemisinin-resistant alleles arose independently across Thailand. A total of seven K13 mutant alleles were found (N458Y, R539T, E556D, P574L, R575K, C580Y, S621F). Notably, the R575K and S621F mutations have previously not been reported in Thailand. The most prevalent artemisinin resistance-associated K13 mutation, C580Y, carried two distinct haplotype profiles that were separated based on geography, along the Thai-Cambodia and Thai-Myanmar borders. It appears these two haplotypes may have independent evolutionary origins. In summary, parasites with K13 propeller mutations associated with artemisinin resistance were widely present along the Thai-Cambodia and Thai-Myanmar borders prior to the implementation of the artemisinin resistance containment project in the region.

The prevention and treatment of obstetric fistula still remains a concern and a challenge in low income countries. The objective of this study was to estimate the overall proportions of failure of fistula closure and incontinence among women undergoing repair for obstetric fistula in Guinea and identify its associated factors.

This analysis evaluated the immune response to the two-dose, heterologous Ad26.ZEBOV, MVA-BN-Filo Ebola virus vaccine regimen, administered 56-days apart, from multiple African sites based on results from one analytic laboratory.

In 2015, the laboratory at the Ebola treatment center in Coyah, Guinea, confirmed Ebola virus disease (EVD) in 286 patients. The cycle threshold (Ct) of an Ebola virus-specific reverse transcription-polymerase chain reaction assay and 13 blood chemistry parameters were measured on admission and during hospitalization. Favipiravir treatment was offered to patients with EVD on a compassionate-use basis.

Multiplex bead assays (MBA) that measure IgG antibodies to the carboxy-terminal 19-kDa sub-unit of the merozoite surface protein 1 (MSP119) are currently used to determine malaria seroprevalence in human populations living in areas with both stable and unstable transmission. However, the species specificities of the IgG antibody responses to the malaria MSP119 antigens have not been extensively characterized using MBA.

Social network structure is a fundamental determinant of human health, from infectious to chronic diseases. However, quantitative and unbiased approaches to measuring social network structure are lacking. We hypothesized that genetic relatedness of oral commensal bacteria could be used to infer social contact between humans, just as genetic relatedness of pathogens can be used to determine transmission chains of pathogens. We used a traditional, questionnaire survey-based method to characterize the contact network of the School of Public Health at a large research university. We then collected saliva from a subset of individuals to analyze their oral microflora using a modified deep sequencing multilocus sequence typing (MLST) procedure. We examined micro-evolutionary changes in the S. viridans group to uncover transmission patterns reflecting social network structure. We amplified seven housekeeping gene loci from the Streptococcus viridans group, a group of ubiquitous commensal bacteria, and sequenced the PCR products using next-generation sequencing. By comparing the generated S. viridans reads between pairs of individuals, we reconstructed the social network of the sampled individuals and compared it to the network derived from the questionnaire survey-based method. The genetic relatedness significantly (p-value < 0.001) correlated with social distance in the questionnaire-based network, and the reconstructed network closely matched the network derived from the questionnaire survey-based method. Oral commensal bacterial are thus likely transmitted through routine physical contact or shared environment. Their genetic relatedness can be used to represent a combination of social contact and shared physical space, therefore reconstructing networks of contact. This study provides the first step in developing a method to measure direct social contact based on commensal organism genotyping, potentially capable of unmasking hidden social networks that contribute to pathogen transmission.

Recent anti-malarial resistance monitoring in Angola has shown efficacy of artemether-lumefantrine (AL) in certain sites approaching the key 90% lower limit of efficacy recommended for artemisinin-based combination therapy. In addition, a controversial case of malaria unresponsive to artemisinins was reported in a patient infected in Lunda Sul Province in 2013.

The potential consequences of parasitic infections on a person's immune responsiveness to unrelated antigens are often conjectured upon in relationship to allergic responses and autoimmune diseases. These considerations sometimes extend to whether parasitic infection of pregnant women can influence the outcomes of responses by their offspring to the immunizations administered during national Expanded Programs of Immunization. To provide additional data to these discussions, we have enrolled 99 close-to-term pregnant women in western Kenya and determined their Schistosoma mansoni and Plasmodium falciparum infection status. At 2 years of age, when the initial immunization schedule was complete, we determined their children's IgG antibody levels to tetanus toxoid, diphtheria toxoid, and measles nucleoprotein (N-protein) antigens using a multiplex assay. We also monitored antibody responses during the children's first 2 years of life to P. falciparum MSP119 (PfMSP119), S. mansoni Soluble Egg Antigen (SEA), Ascaris suum hemoglobin (AsHb), and Strongyloides stercoralis (SsNIE). Mothers' infections with either P. falciparum or S. mansoni had no impact on the level of antibody responses of their offspring or the proportion of offspring that developed protective levels of antibodies to either tetanus or diphtheria antigens at 2 years of age. However, children born of S. mansoni-positive mothers and immunized for measles at 9 months of age had significantly lower levels of anti-measles N-protein antibodies when they were 2 years old (p = 0.007) and a lower proportion of these children (62.5 vs. 90.2%, OR = 0.18, 95% CI = 0.04-0.68, p = 0.011) were considered positive for measles N-protein antibodies. Decreased levels of measles antibodies may render these children more susceptible to measles infection than children whose mothers did not have schistosomiasis. None of the children demonstrated responses to AsHb or SsNIE during the study period. Anti-SEA and anti-PfMSP119 responses suggested that 6 and 70% of the children acquired schistosomes and falciparum malaria, respectively, during the first 2 years of life.

Universal coverage with long-lasting insecticidal nets (LLINs) is a primary control strategy against Plasmodium falciparum malaria. However, its impact on the three other main species of human malaria and lymphatic filariasis (LF), which share the same vectors in many co-endemic areas, is not as well characterized. The recent development of multiplex antibody detection provides the opportunity for simultaneous evaluation of the impact of control measures on the burden of multiple diseases.

The ability to identify mixed-species infections and track the origin of Plasmodium parasites can further enhance the development of treatment and prevention recommendations as well as outbreak investigations. Here, we explore the utility of using the full Plasmodium mitochondrial genome to classify Plasmodium species, detect mixed infections, and infer the geographical origin of imported P. falciparum parasites to the United States (U.S.). Using the recently developed standardized, high-throughput Malaria Resistance Surveillance (MaRS) protocol, the full Plasmodium mitochondrial genomes of 265 malaria cases imported to the U.S. from 2014-2017 were sequenced and analyzed. P. falciparum infections were found in 94.7% (251/265) of samples. Five percent (14/265) of samples were identified as mixed- Plasmodium species or non-P. falciparum, including P. vivax, P. malariae, P. ovale curtisi, and P. ovale wallikeri. P. falciparum mitochondrial haplotypes analysis revealed greater than eighteen percent of samples to have at least two P. falciparum mitochondrial genome haplotypes, indicating either heteroplasmy or multi-clonal infections. Maximum-likelihood phylogenies of 912 P. falciparum mitochondrial genomes with known country origin were used to infer the geographical origin of thirteen samples from persons with unknown travel histories as: Africa (country unspecified) (n = 10), Ghana (n = 1), Southeast Asia (n = 1), and the Philippines (n = 1). We demonstrate the utility and current limitations of using the Plasmodium mitochondrial genome to classify samples with mixed-infections and infer the geographical origin of imported P. falciparum malaria cases to the U.S. with unknown travel history.

Lingering post-treatment parasite antigen in blood complicates malaria diagnosis through antigen detection. Characterization of antigen clearance dynamics is important for interpretation of positive antigen detection tests.