Intermittent preventive treatment for forest goers by forest malaria workers: an observational study on a key intervention for malaria elimination in Cambodia.

Background: Cambodia targets P. falciparum malaria elimination by 2023 and all human malaria species by 2025, aligning with WHO's Mekong Malaria Elimination program. The Intermittent Preventive Treatment for Forest Goers (IPTf) project aimed at forest-specific malaria elimination. The study aims to pinpoint the main factors driving malaria transmission in Cambodian forests and evaluate the initial implementation and effectiveness of IPTf in accelerating the elimination of malaria by treating and preventing infections among at-risk populations in these areas. Methods: From March 11, 2019, to January 30, 2021, a malaria intervention program took place in isolated forests in Northeast Cambodia. The first phase focused on observing forest goers (FGs) within the forests, documenting their malaria risk. In the second phase, a monthly artesunate-mefloquine IPTf was implemented by trained forest malaria workers who were former FGs conducting interviews, blood collection, and IPTf administration. Findings: Throughout the two-year period, 2198 FGs were involved in 3579 interviews, with 284 in both the observation and intervention phases. Following IPTf implementation, PCR-confirmed malaria prevalence significantly decreased from 2.9% to 0.5% for P. falciparum and from 21.0% to 4.7% for P. vivax. Among the 284 participants tracked through both phases, malaria prevalence fell from 2.5% to 0.3% for P. falciparum and from 22.5% to 3.7% for P. vivax. The intervention phase demonstrated a rapid decline in P. falciparum prevalence among mobile and previously inaccessible populations, while also revealing a higher P. falciparum infection risk associated with activities inaccurately labelled as farming, underscoring the need for customized interventions. Interpretation: The successful implementation of IPTf in Cambodia's remote forests has markedly decreased malaria prevalence among high-risk groups. Cambodia's National Malaria Program has acknowledged this strategy as essential for malaria elimination intervention, endorsing forest-specific approaches to meet the 2025 goal of eradicating all human malaria species in Cambodia. Funding: The study received funding from the French 5% Initiative (Initiative Canal 2-17SANIN205).

Pediatric urogenital schistosomiasis diagnosed in France.

BACKGROUND: Schistosomiasis affects approximately 230 million people worldwide. There is an increased incidence of schistosomiasis cases in France acquired from outside the country. This increases the risk of schistosomiasis outbreaks as observed in Corsica. Clinicians from non-endemic regions are not accustomed to diagnosing and managing this pathology. The objective of this study is to provide a better description of the clinical and paraclinical characteristics and disease evolution of affected children. METHODS: Through the French Pediatric Nephrology Society and the Pediatric Infectious Pathology Group, we contacted all French pediatric centers that may have treated children with urinary schistosomiasis between 2013 and 2019. Age, sex, comorbidities, and clinical, biological, and radiological data (at discovery and follow-up) were collected retrospectively. RESULTS: A total of 122 patients from 10 different centers were included. The median age was 14 years and the sex ratio M/F was 4:1. Hematuria was present in 82% of the patients while urinary tract abnormality was found in 36% of them. Fourteen patients (11%) displayed complicated forms of urinary schistosomiasis including 10 patients with chronic kidney disease. A total of 110 patients received treatment with praziquantel, which was well-tolerated and led to clinical resolution of symptoms in 98% of cases. CONCLUSION: Patients with schistosomiasis present frequent kidney, urinary, or genital involvement. Systematic screening of patients returning from endemic areas is therefore recommended, especially since treatment with antiparasitic drugs is effective and well-tolerated. Enhancing medical knowledge of this pathology among all practitioners is essential to improve care and outcomes.

Rapid and Accurate Diagnosis of Dermatophyte Infections Using the DendrisCHIP® Technology.

Dermatophytosis is a superficial fungal infection with an ever-increasing number of patients. Culture-based mycology remains the most commonly used diagnosis, but it takes around four weeks to identify the causative agent. Therefore, routine clinical laboratories need rapid, high throughput, and accurate species-specific analytical methods for diagnosis and therapeutic management. Based on these requirements, we investigated the feasibility of DendrisCHIP® technology as an innovative molecular diagnostic method for the identification of a subset of 13 pathogens potentially responsible for dermatophytosis infections in clinical samples. This technology is based on DNA microarray, which potentially enables the detection and discrimination of several germs in a single sample. A major originality of DendrisCHIP® technology is the use of a decision algorithm for probability presence or absence of pathogens based on machine learning methods. In this study, the diagnosis of dermatophyte infection was carried out on more than 284 isolates by conventional microbial culture and DendrisCHIP®DP, which correspond to the DendrisCHIP® carrying oligoprobes of the targeted pathogens implicated in dermatophytosis. While convergence ranging from 75 to 86% depending on the sampling procedure was obtained with both methods, the DendrisCHIP®DP proved to identify more isolates with pathogens that escaped the culture method. These results were confirmed at 86% by a third method, which was either a specific RT-PCR or genome sequencing. In addition, diagnostic results with DendrisCHIP®DP can be obtained within a day. This faster and more accurate identification of fungal pathogens with DendrisCHIP®DP enables the clinician to quickly and successfully implement appropriate antifungal treatment to prevent the spread and elimination of dermatophyte infection. Taken together, these results demonstrate that this technology is a very promising method for routine diagnosis of dermatophytosis.

Evolution and spread of Plasmodium falciparum mutations associated with resistance to sulfadoxine-pyrimethamine in central Africa: a cross-sectional study.

BACKGROUND: Efficacy of sulfadoxine-pyrimethamine, the malaria chemoprophylaxis used in pregnant women, and in children when combined with amodiaquine, is threatened by the accumulation of mutations in the Plasmodium falciparum dihydropteroate synthase (pfdhps) and dihydrofolate reductase (pfdhfr) genes. Data on the prevalence of resistant alleles in central Africa and the new pfdhps I431V mutation, particularly associated with other mutations to form the pfdhps vagKgs allele, are scarce. We explored the frequency and geographical distribution of pfdhps and pfdhfr mutations in central Africa in 2014-18, and assessed the evolutionary origin of the vagKgs allele. METHODS: Samples were collected at 18 health-care centres in seven countries (Angola, Cameroon, Central African Republic, Democratic Republic of the Congo, Gabon, Nigeria, and Republic of the Congo) from patients who showed possible symptoms of malaria between March 1, 2014, and Oct 31, 2018. Samples that were positive for P falciparum were transported to a laboratory in Toulouse, France, and genotyped. The frequency of pfdhfr and pfdhps mutations was studied in 1749 samples. Microsatellites in pfdhps flanking regions and whole-genome analysis compared with parasite genomes from the data-sharing network MalariaGEN were performed on samples carrying the vagKgs allele. FINDINGS: Mapping of the prevalence of single nucleotide polymorphisms and corresponding alleles of pfdhfr and pfdhps showed a substantial spread of alleles associated with sulfadoxine-pyrimethamine resistance in central Africa during the 2014-18 period, especially an increase going west to east in pfdhps alleles carrying the K540E and A581G mutations. A high prevalence of the pfdhps I431V mutation was observed in Cameroon (exceeding 50% in the northern region) and Nigeria. Genomic analysis showed a recent African emergence and a clonal expansion of the most frequent pfdhps vagKgs allele. INTERPRETATION: Reduced sulfadoxine-pyrimethamine efficacy due to increased resistance is a worrying situation, especially because the malaria transmission level is high in central Africa. Although the resistance phenotype remains to be confirmed, the emergence and spread of the vagKgs allele in west and central Africa could challenge the use of sulfadoxine-pyrimethamine. FUNDING: Toulouse Institute for Infectious and Inflammatory Diseases.

Epidemiological, Clinical and Laboratory Features of Strongyloidiasis in 69 Attendees at a French Outpatient Clinic.

The present retrospective study analyzed the characteristics of strongyloidiasis in patients who were diagnosed at the Outpatient Clinic of the Department of Parasitology-Mycology, Toulouse, France. Sixty-nine file records were included in the study on the basis of a positive stool examination that used Baermann's method. The prominent epidemiological findings were the presence of former immigrants from Italy or Portugal, veterans from the 1st Indochina war, and autochthonous cases. Almost 1/4 of the patients were asymptomatic. Manifestations of skin allergy were the main clinical feature. Blood eosinophilia was present in 76.8% of the patients, and serum total IgE was ≥150 kIU/L in 79.7%. Immunodiagnosis was achieved from 1990 to 2001 by indirect immunofluorescence (IFAT) that was then replaced with ELISA, both methods using Strongyloides ratti filariform larvae. ELISA was found to be similar to IFAT in terms of specificity but exhibited a greater sensitivity. Patients were primarily treated with albendazole or ivermectin beginning in 1993. Forty-eight patients attended the follow-up consultation. Kinetics of the clinical picture and blood eosinophilia were found to be the most convenient parameters to assess the efficacy of anthelmintic therapy. In conclusion, strongyloidiasis remains a neglected disease in Southwestern France. The resolution of clinical features along with the kinetics of eosinophilia appeared to be the most appropriate parameters to check during the posttreatment follow-up.

Evaluation of the Performance of the Novodiag® Stool Parasites Assay for the Detection of Intestinal Protozoa and Microsporidia.

OBJECTIVES: We aimed to assess the performance of the Novodiag® Stool Parasites (NSP) assay in the diagnosis of the most common intestinal protozoan and microsporidia infections. METHODS: A panel of 167 selected stool samples was retrospectively analysed with the NSP assay and compared to routine microscopy and qPCR methods for the detection of pathogenic protozoa and microsporidia. RESULTS: Whereas specificity was high for all protozoa and microsporidia, NSP sensitivity was strongly dependent on the comparative method used as reference. When compared to microscopic methods, NSP sensitivity was high (96.7 to 100%) for Blastocystis hominis, Entamoeba histolytica and Cyclospora cayetanensis but was lower for Giardia intestinalis (85.2%) and ≤50% for Cystoisospora belli and Dientamoeba fragilis. In comparison to conventional qPCR, the NSP assay demonstrated lower sensitivity characteristics dependent on parasite loads, reaching 60 to 70% for G. intestinalis, D. fragilis, Cryptosporidium spp. and E. histolytica. Sensitivity was 100% for Enterocytozoon bieneusi, but none of the five samples containing Encephalitozoon spp. were detected. CONCLUSIONS: The overall performance of the NSP assay in the diagnosis of gastrointestinal protozoa and microsporidia seems to be better than or equivalent to that observed with microscopic methods but inferior to that obtainable with classical targeted qPCR.

Influence of the sickle cell trait on Plasmodium falciparum infectivity from naturally infected gametocyte carriers.

BACKGROUND: Sickle cell trait (SCT) refers to the carriage of one abnormal copy of the ß-globin gene, the HbS allele. SCT offers protection against malaria, controlling parasite density and preventing progression to symptomatic malaria. However, it remains unclear whether SCT also affects transmission stages and mosquito infection parameters. Deciphering the impact of the SCT on human to mosquito malaria transmission is key to understanding mechanisms that maintain the trait in malaria endemic areas. METHODS: The study was conducted from June to July 2017 among asymptomatic children living in the locality of Mfou, Cameroon. Blood samples were collected from asymptomatic children to perform malaria diagnosis by microscopy, Plasmodium species by PCR and hemoglobin typing by RFLP. Infectiousness of gametocytes to mosquitoes was assessed by membrane feeding assays using blood from gametocyte carriers of HbAA and HbAS genotypes. A zero-inflated model was fitted to predict distribution of oocysts in mosquitoes according to hemoglobin genotype of the gametocyte source. RESULTS: Among the 1557 children enrolled in the study, 314 (20.16%) were of the HbAS genotype. The prevalence of children with P. falciparum gametocytes was 18.47% in HbAS individuals and 13.57% in HbAA, and the difference is significant (χ2 = 4.61, P = 0.032). Multiplicity of infection was lower in HbAS gametocyte carriers (median = 2 genotypes/carrier in HbAS versus 3.5 genotypes/carrier in HbAA, Wilcoxon sum rank test = 188, P = 0.032). Gametocyte densities in the blood donor significantly influenced mosquito infection prevalence in both HbAS and HbAA individuals. The HbAS genotype had no significant effect on mosquito infection outcomes when using immune or naïve serum in feeding assays. In AB replacement feeding experiments, the odds ratio of mosquito infection for HbAA blood as compared to HbAS was 0.56 (95% CI 0.29-1.10), indicating a twice higher risk of infection in mosquitoes fed on gametocyte-containing blood of HbAS genotype. CONCLUSION: Plasmodium transmission stages were more prevalent in SCT individuals. This may reflect the parasite's enhanced investment in the sexual stage to increase their survival rate when asexual replication is impeded. The public health impact of our results points the need for intensive malaria control interventions in areas with high prevalence of HbAS. The similar infection parameters in feeding experiments where mosquitoes received the original serum from the blood donor indicated that immune responses to gametocyte surface proteins occur in both HbAS and HbAA individuals. The higher risk of infection in mosquitoes fed on HbAS blood depleted of immune factors suggests that changes in the membrane properties in HbAS erythrocytes may impact on the maturation process of gametocytes within circulating red blood cells.

Effect of sulfadoxine-pyrimethamine chemoprophylaxis in pregnant women on selection of the new P. falciparum dhps quintuple mutant carrying the I431V mutation.

BACKGROUND: A new mutation in the Plasmodium falciparum dihydropteroate synthetase gene (pfdhps), I431V, has been identified in several countries of Central and West Africa. This mutation is mostly found in association with four other SNPs on pfdhps (S436A, A437G, A581G and A613S), forming a quintuple mutant (vagKgs) and almost always associated with the Plasmodium falciparum dihydrofolate reductase gene (pfdhfr) CirnI (C50R, N51I, S108N) triple mutant. To date, nothing is known about the impact of this new pfdhps genotype on sulfadoxine-pyrimethamine (SP) resistance. OBJECTIVES: We sought to assess the prevalence of this pfdhps vagKgs quintuple mutant in two groups of pregnant women with malaria, one that took intermittent preventive treatment with sulfadoxine-pyrimethamine (IPTp-SP) and one that did not. METHODS: The pfdhfr and pfdhps genes from Plasmodium falciparum isolates collected in Yaoundé (Cameroon) from pregnant women with symptomatic malaria under IPTp-SP or not, were sequenced. RESULTS: Of 159 patients evaluated, 70 had already taken SP during pregnancy and 89 had never taken SP. Only the vagKgs allele was significantly overrepresented in the SP+ group (21.4% versus 3.4%; P < 0.001), whereas the ISgKAA mutant, widely distributed in this area and known to be less susceptible to SP, tended to be less abundant in this group (48.6% versus 64.0%; P = 0.0503). CONCLUSIONS: We found a strong overrepresentation of the CirnI/vagKgs haplotype in the IPTp-SP pregnant group, suggesting a high level of resistance of this mutant to SP. This could compromise not only the effectiveness of IPTp-SP but also the seasonal malaria chemoprevention of young children, now widely implemented.

Fatal mucormycosis and aspergillosis coinfection associated with haemophagocytic lymphohistiocytosis: A case report and literature review.

Invasive mould infections are life-threatening and mainly occur in immunocompromised patients. Whereas aspergillosis is described during haemophagocytic lymphohistiocytosis (HLH), only a few cases of concomitant mucormycosis with HLH have been reported. Here, we present an uncommon coinfection of mucormycosis and aspergillosis associated with HLH probably due to a varicella zoster virus (VZV) viraemia which was unresponsive to triple antifungal therapy (liposomal amphotericin B combined with isavuconazole and caspofungin). A review of the cases of mucormycosis with HLH showed that this uncommon association was always lethal and underscored the relevance of screening for mould infections in patients with HLH.

Immune recovery-related patterns of post kala-azar dermal and ocular leishmaniasis in people living with HIV.

OBJECTIVE: Post kala-azar dermal leishmaniasis (PKDL) is a rare complication of visceral leishmaniasis. We aimed at reporting PKDL cases in people living with HIV (PLHIV) and compare their characteristics based on whether PKDL occurred in the context of immune recovery under antiretroviral therapy (ART) or not. DESIGN: National survey and literature review. METHODS: We called for observations in France in October 2020 and performed a literature review from PubMed (Medline) and Web of Science up to December 2020. Two groups of patients were defined based on whether PKDL occurred in the context of immune recovery under ART (group 1) or not (group 2), and compared. RESULTS: Three PLHIV with PKDL identified in France in the last decade were described and added to 33 cases from the literature. Compared with group 2 (16/36, 44.4%), patients from group 1 (20/36, 55.6%) originated more frequently from Europe (12/20, 60% vs. 2/16, 12.5%; P  = 0.0038), had higher median blood CD4 + cell counts (221/µl vs. 61/µl; P  = 0.0005) and increase under ART (122/µl, interquartile range 73-243 vs. 33/µl, interquartile range 0-53; P  = 0.0044), had less frequently concomitant visceral leishmaniasis (3/20, 15% vs. 8/12, 66.7%; P  = 0.006), and a trend to more frequent ocular involvement (7/20, 35% vs. 1/16, 6.25%; P  = 0.0531). CONCLUSION: In PLHIV, PKDL occurs after a cured episode of visceral leishmaniasis as part of an immune restoration disease under ART, or concomitant to a visceral leishmaniasis relapse in a context of AIDS. For the latter, the denomination 'disseminated cutaneous lesions associated with visceral leishmaniasis' seems more accurate than PKDL.

Genetic Diversity of Plasmodium falciparum and Distribution of Antimalarial Drug Resistance Mutations in Symptomatic and Asymptomatic Infections.

Malaria control relies on passive case detection, and this strategy fails detecting asymptomatic infections. In addition, infections in endemic areas harbor multiple parasite genotypes that could affect case management and malaria epidemiology. Here, we performed AmpSeq genotyping to capture polymorphisms associated with antimalarial resistance and the genetic diversity within natural Plasmodium falciparum infections. Known genetic polymorphisms associated with altered drug susceptibility were screened for the five most common marker genes, pfdhfr, pfdhps, pfmdr1, pfcrt, and pfK13, and genetic diversity was established from two known AmpSeq markers, cpmp and csp. Relative abundance of the different genotypes within mixed infections was calculated from the number of reads per genotype. Genotyping was performed on 117 samples, 63 from asymptomatic and 54 from symptomatic individuals. We identified up to 15 genotypes within an infection, and the median multiplicity of infection was higher in asymptomatic infections (median MOI = 5 in asymptomatics versus median MOI = 2 in symptomatics, P < 0.001). No genetic differentiation on parasites from asymptomatic and symptomatic individuals was found. No mutation associated with ART resistance was identified. Prevalence of the P. falciparum chloroquine resistance wild-type genotype (CVMNK) reached 80%, confirming a return to chloroquine (CQ) sensitive parasites in Cameroon. In addition, the CQ-associated resistant genotype (CVIET) was present at very low density in polyclonal infections. Persistence of low-density chloroquine resistant parasites indicates competition-survival trade-offs may contribute to maintaining genetic diversity in natura. Thus, monitoring the expansion of these low-density genotypes in different immune backgrounds will be critical to evaluate drug policy changes.

A Retrospective Study of the Efficacy of Albendazole and Diethylcarbamazine for the Treatment of Human Toxocariasis.

In the Department of Parasitology and Mycology of Toulouse University Hospitals, patients presenting with common/covert toxocariasis were treated either with albendazole (39 cases) or with diethylcarbamazine (32 cases). Albendazole (ABZ) was given at 10 mg/kg b/w daily for 14 days, and diethylcarbamazine (DEC) was given at 4 mg/kg b/w daily for 21 days. In both groups, follow-up consultations occurred approximately 48 days after the end of the anthelmintic therapy. ABZ and DEC displayed a similar efficacy on the kinetics of the clinical picture (-64.5% of reduction vs. -72.7%, respectively) and on the levels of blood eosinophilia, serum eosinophil cationic protein and serum total IgE. However, the effect of the medication on the laboratory parameters was moderate. The rate of adverse reactions was similar in both groups (38% for ABZ vs. 31% for DEC), but DEC-treated patients complained of more intense and long-lasting side effects. The DEC group had more major adverse reactions, resulting in the termination of the anthelmintic treatment. The results from this retrospective study bring further arguments for considering ABZ, given at 10 mg/kg daily for 2 weeks, as the drug of choice in the treatment of human toxocariasis.

A Clustered Case Series of Mucorales Detection in Respiratory Samples from COVID-19 Patients in Intensive Care, France, August to September 2021.

While COVID-19-associated pulmonary aspergillosis is now well described in developed countries, COVID-19-associated mucormycosis (CAM) has seemed to remain quite rare in Europe. A retrospective study was performed between March 2020 to September 2021 among COVID-19 adult patients in the intensive care unit (ICU) at Toulouse Hospital (Southern France). PCR screening on respiratory samples, which target Aspergillus or Mucorales DNA, were performed, and the number of fungal detections was evaluated monthly during the study period. During the 19 months of the study, 44 (20.3%) COVID-19 ICU patients had a positive PCR for Aspergillus, an overall rate in keeping with the incidence of ICU COVID-19 patients. Ten patients (7.1%) had a positive Mucorales PCR over the same period. Surprisingly, 9/10 had a positive Mucor/Rhizopus PCR in August-September 2021, during the fourth Delta SARS-CoV-2 variant wave. Epidemic investigations have identified a probable environmental cause linked to construction works in the vicinity of the ICU (high levels of airborne spores due to the mistaken interruption of preventive humidification and summer temperature). Even if CAM are apparently rare in Europe, a cluster can also develop in industrialised countries when environmental conditions (especially during construction work) are associated with a high number of COVID-19 patients in the ICU.

The Rare, the Best: Spread of Antimalarial-Resistant Plasmodium falciparum Parasites by Anopheles Mosquito Vectors.

The emergence of resistance to antimalarials has prompted the steady switch to novel therapies for decades. Withdrawal of antimalarials, such as chloroquine in sub-Saharan Africa in the late 1990s, led to rapid declines in the prevalence of resistance markers after a few years, raising the possibility of reintroducing them for malaria treatment. Here, we provide evidence that the mosquito vector plays a crucial role in maintaining parasite genetic diversity. We followed the transmission dynamics of Plasmodium falciparum parasites through its vector in natural infections from gametocytes contained in the blood of asymptomatic volunteers until sporozoites subsequently developed in the mosquito salivary glands. We did not find any selection of the mutant or wild-type pfcrt 76 allele during development in the Anopheles mosquito vector. However, microsatellite genotyping indicated that minority genotypes were favored during transmission through the mosquito. The analysis of changes in the proportions of mutant and wild-type pfcrt 76 alleles showed that, regardless of the genotype, the less-represented allele in the gametocyte population was more abundant in mosquito salivary glands, indicating a selective advantage of the minority allele in the vector. Selection of minority genotypes in the vector would explain the persistence of drug-resistant alleles in the absence of drug pressure in areas with high malaria endemicity and high genetic diversity. Our results may have important epidemiological implications, as they predict the rapid re-emergence and spread of resistant genotypes if antimalarials that had previously selected resistant parasites are reintroduced for malaria prevention or treatment. IMPORTANCE Drug selection pressure in malaria patients is the cause of the emergence of resistant parasites. Resistance imposes a fitness cost for parasites in untreated infections, so withdrawal of the drug leads to the return of susceptible parasites. Little is known about the role of the malaria vector in this phenomenon. In an experimental study conducted in Cameroon, an area of high malaria transmission, we showed that the vector did not favor the parasites based on sensitivity or resistance criteria, but it did favor the selection of minority clones. This finding shows that the vector increases the diversity of plasmodial populations and could play an important role in falciparum malaria epidemiology by maintaining resistant clones despite the absence of therapeutic pressure.

Immune Response in Pneumocystis Infections According to the Host Immune System Status.

The host immune response is critical in Pneumocystis pneumonia (PCP). Immunocompetent hosts can eliminate the fungus without symptoms, while immunodeficient hosts develop PCP with an unsuitable excessive inflammatory response leading to lung damage. From studies based on rodent models or clinical studies, this review aimed to better understand the pathophysiology of Pneumocystis infection by analysing the role of immune cells, mostly lymphocytes, according to the immune status of the infected host. Hence, this review first describes the immune physiological response in infected immunocompetent hosts that are able to eliminate the fungus. The objective of the second part is to identify the immune elements required for the control of the fungus, focusing on specific immune deficiencies. Finally, the third part concentrates on the effect of the different immune elements in immunocompromised subjects during PCP, to better understand which cells are detrimental, and which, on the contrary, are beneficial once the disease has started. This work highlights that the immune response associated with a favourable outcome of the infection may differ according to the immune status of the host. In the case of immunocompetency, a close communication between B cells and TCD4 within tertiary lymphocyte structures appears critical to activate M2 macrophages without much inflammation. Conversely, in the case of immunodeficiency, a pro-inflammatory response including Th1 CD4, cytotoxic CD8, NK cells, and IFNγ release seems beneficial for M1 macrophage activation, despite the impact of inflammation on lung tissue.

New Insights into Blood Circulating Lymphocytes in Human Pneumocystis Pneumonia.

The host lymphocyte response is decisive in Pneumocystis pneumonia (PCP) pathophysiology but little is known of the specific roles of lymphocyte subpopulations in this fungal infection. Peripheral NK, NKT, B, TCD4+ and TCD8+ subpopulations were compared by immunophenotyping between 20 patients diagnosed with PCP (PCP(+)] and 20 uninfected immunosuppressed patients (PCP(-)). Among PCP(+) subjects, the lymphocyte populations were also compared between surviving and deceased patients. Low B cell count (<40 cells/µL) was more frequent in PCP(+) than in PCP(-) patients (p = 0.03), while there was no difference for the TCD4 count. Among the PCP(+) group, the 7 deceased patients had lower Th1 (p = 0.02) and Tc1 (p = 0.03) populations, higher Th2 response (p = 0.03), higher effector TCD8 (p < 0.01), lower central memory TCD8 (p = 0.04) and reduced NK cells (p = 0.02) compared with the 13 survivors. Th1/Th2 ratio < 17, CD8 Tc1 < 44%, effector TCD8 < 25%, central memory TCD8 < 4%, NK cells < 50 cells/µL and total lymphocytes < 0.75 G/L were associated with a higher risk of mortality (p = 0.003, p = 0.007, p = 0.0007, p = 0.004, p = 0.02 and p = 0.019, respectively). The traditional analysis of TCD4 and TCD8 populations may be insufficient in the context of PCP. It could be completed by using B cells to predict the risk of PCP, and by using lymphocyte subpopulations or total lymphocyte count, which are easy to obtain in all health care facilities, to evaluate PCP prognosis.

Antimalarial drug resistance in the Central and Adamawa regions of Cameroon: Prevalence of mutations in P. falciparum crt, Pfmdr1, Pfdhfr and Pfdhps genes.

The spread of Plasmodium falciparum resistant parasites remains one of the major challenges for malaria control and elimination in Sub Saharan Africa. Monitoring of molecular markers conferring resistance to different antimalarials is important to track the spread of resistant parasites and to optimize the therapeutic lifespan of current drugs. This study aimed to evaluate the prevalence of known mutations in the drug resistance genes Pfcrt, Pfmdr1, Pfdhfr and Pfdhps in two different epidemiological settings in Cameroon. Dried blood spots collected in 2018 and 2019 from asymptomatic individuals were used for DNA extraction and then the Plasmodium infection status was determined byPCR. Detection of SNPs was performed by nested PCR followed by allele-specific restriction analysis (ASRA). The prevalence of each genotype was compared between sites using the Chi square and Fisher's exact tests. A high prevalence of the Pfcrt K76 wild type allele was found in both sites (88.5 and 62.29% respectively; P< 0,0001). The prevalence of Pfmdr1 mutations 86Y and 1246Y was respectively 55.83 and 1.45% in Mfou and 45.87 and 5.97% in Tibati, with significant difference between the studied areas (P<0.0001). Overall, the Pfdhfr triple-mutant genotype (51I/59R/108N) was highly prevalent (> 96%), however no SNP was detected at codon 164. In Pfdhps, the prevalence of the 437G mutation reached (90%) and was at higher frequency in Mfou (P< 0.0001). Overall, the Pfdhps mutations 540E and 581G were less common (0.33 and 3.26%, respectively). The quadruple resistant genotype (Pfdhfr 51I/59R/108N+Pfdhp437G) was found almost 90% of the samples. The wild-type genotype (Pfdhfr N51/C59/S108/164I+Pfdhps A437/K540/A581) was never identified and the sextuple mutant (Pfdhfr 51I/59R/108N+Pfdhp437G/540E/581G), kwon as super resistant appeared in two samples from Tibati. These findings demonstrate declining trends in the prevalence of mutations conferring resistance to 4-aminoquinolines, especially to chloroquine. However, a high level of mutations in P. falciparum genes related to SP resistance was detected and this raises concerns about the future efficacy of IPTp-SP and SMC in Cameroon.

Efficacy of dihydroartemisinin/piperaquine in patients with non-complicated Plasmodium falciparum malaria in Yaoundé, Cameroon.

BACKGROUND: Dihydroartemisinin/piperaquine is increasingly used for the treatment of uncomplicated Plasmodium falciparum malaria in Africa. The efficacy of this combination in Cameroon is poorly documented, while resistance to dihydroartemisinin/piperaquine readily spreads in Southeast Asia. OBJECTIVES: This study evaluated the clinical efficacy of dihydroartemisinin/piperaquine in Cameroon, as well as the molecular profile and phenotypic susceptibility of collected isolates to dihydroartemisinin and piperaquine. PATIENTS AND METHODS: Dihydroartemisinin/piperaquine efficacy in 42 days was followed-up for 138 patients presenting non-complicated falciparum malaria. Piperaquine concentration was determined at day 7 for 124 patients. kelch13 gene polymorphisms (n = 150) and plasmepsin2 gene amplification (n = 148) were determined as molecular markers of resistance to dihydroartemisinin and piperaquine, respectively. Parasite susceptibility to dihydroartemisinin and piperaquine was determined using validated in vitro survival assays. RESULTS: The efficacy of dihydroartemisinin/piperaquine treatment was 100% after PCR correction. The reinfections were not associated with a variation of piperaquine concentration at day 7. Ninety-six percent (144/150) of the samples presented a WT allele of the kelch13 gene. Two percent (3/150) presented the non-synonymous mutation A578S, which is not associated with resistance to dihydroartemisinin. No duplication of the plasmepsin2 gene was observed (0/148). All the samples tested in vitro by survival assays (n = 87) were susceptible to dihydroartemisinin and piperaquine. CONCLUSIONS: Dihydroartemisinin/piperaquine has demonstrated excellent therapeutic efficacy with no evidence of emerging artemisinin or piperaquine resistance in Yaoundé, Cameroon. This observation suggests that dihydroartemisinin/piperaquine could be a sustainable therapeutic solution for P. falciparum malaria if implemented in areas previously free of artemisinin- and piperaquine-resistant parasites, unlike Southeast Asia.

Characteristics and outcome according to underlying disease in non-AIDS patients with acute respiratory failure due to Pneumocystis pneumonia.

In the non-AIDS group, several underlying conditions and immune defects could lead to different PCP presentations. This study compared PCP presentation and outcome according to the underlying disease. A secondary analysis of a previously published prospective observational study including 544 PCP patients was done. Only non-AIDS patients were included. Underlying disease was defined as chronic lymphocytic leukemia (CLL), organ transplantation, solid cancer, allogeneic hematopoietic stem cell transplant (AHSCT), other hematological diseases, and immunosuppressive treatment. Clinical characteristics and outcomes were compared between groups. Multiple correspondent analyses compared clinical characteristics at diagnosis. Day 30 mortality was analyzed. Three hundred and twenty-one patients were included in the study. The underlying diseases were hematological malignancy (n = 75), AHSCT (n = 14), CLL (n = 19), solid organ transplant (n = 94), solid tumor (n = 39), and immunosuppressive treatment (n = 57). Compared with other underlying diseases, PCP related to CLL was closer to PCP related to AIDS presentation (long duration of symptoms before diagnosis, high level of dyspnea, and low oxygen saturation at diagnosis). Day 30 mortality was associated with underlying disease, oxygen flow, and shock at ICU admission. PCP presentations may vary according to the underlying reason for immunosuppression. Response to treatment and adjuvant steroid therapy should be analyzed regarding this result.