Pub Date : 2024-06-11DOI: 10.3389/fitd.2024.1354119
S. Kayuni, Lucas J. Cunningham, Dingase Kumwenda, Bright Mainga, D. Lally, P. Chammudzi, D. Kapira, G. Namacha, Bessie Ntaba, Alice Chisale, Tereza Nchembe, Luis Kinley, Ephraim Chibwana, A. Juhász, Sam Jones, J. Archer, P. Makaula, John Chiphwanya, E. J. LaCourse, J. Musaya, J. R. Stothard
Female genital schistosomiasis (FGS) remains an often overlooked chronic complication of urogenital schistosomiasis in adolescent girls and women. Moreover, the role of zoonotic or hybrid schistosome infection(s) is poorly appreciated, but is increasingly becoming an emerging public health concern in sub-Saharan Africa. In Southern Malawi, during the “Hybridization in UroGenital Schistosomiasis (HUGS)” study visit, we describe the case of a 33-year-old woman with suspected FGS who partook in a detailed external assessment with internal cervical examination using a portable colposcope. She provided several biological samples for analysis with traditional and molecular parasitological methods—urine, cervicovaginal lavage (CVL), cervical swabs, and external mass and cervical biopsies—alongside provision of detailed demographic information after a thorough medical history questionnaire and an in-depth interview. These samples were screened for the presence of Schistosoma ova on microscopy and DNA genotyping using a novel real-time PCR assay in parallel to pre-published probe-based PCR assays capable of identifying and discriminating up to six named Schistosoma species. A further molecular screen of sexually transmitted infections (STIs) including Trichomonas vaginalis, Chlamydia spp., and human papilloma virus (HPV) was conducted on her genital swab and CVL. Overt FGS was diagnosed on clinical colposcopy alongside inspection of the cervical biopsy by microscopy, real-time PCR, and histopathology. The urine filtration, microscopy and real-time PCR of the CVL and swab were negative. This evidences the typical diagnostic challenge, and cases such as this will pose an unmet need in satisfactory patient management. In addition to Schistosoma haematobium, the presence of the zoonotic species Schistosoma mattheei and concurrent STIs raise questions as to the long-term effectiveness of the current control strategies of the National Control Programme to eliminate schistosomiasis as a public health problem. Improved availability of and regular accessibility to praziquantel treatment for women at risk such as this are urgently needed. Furthermore, targeted health education, increased community awareness, and dovetailing of synergistic activities and strategies with other health stakeholders such as those in sexual and reproductive health, as well as HIV/AIDS programs in the Ministry of Health, are needed here and in neighboring countries.
{"title":"Challenges in the diagnosis and control of female genital schistosomiasis in sub-Saharan Africa: an exemplar case report associated with mixed and putative hybrid schistosome infection in Nsanje District, Southern Malawi","authors":"S. Kayuni, Lucas J. Cunningham, Dingase Kumwenda, Bright Mainga, D. Lally, P. Chammudzi, D. Kapira, G. Namacha, Bessie Ntaba, Alice Chisale, Tereza Nchembe, Luis Kinley, Ephraim Chibwana, A. Juhász, Sam Jones, J. Archer, P. Makaula, John Chiphwanya, E. J. LaCourse, J. Musaya, J. R. Stothard","doi":"10.3389/fitd.2024.1354119","DOIUrl":"https://doi.org/10.3389/fitd.2024.1354119","url":null,"abstract":"Female genital schistosomiasis (FGS) remains an often overlooked chronic complication of urogenital schistosomiasis in adolescent girls and women. Moreover, the role of zoonotic or hybrid schistosome infection(s) is poorly appreciated, but is increasingly becoming an emerging public health concern in sub-Saharan Africa. In Southern Malawi, during the “Hybridization in UroGenital Schistosomiasis (HUGS)” study visit, we describe the case of a 33-year-old woman with suspected FGS who partook in a detailed external assessment with internal cervical examination using a portable colposcope. She provided several biological samples for analysis with traditional and molecular parasitological methods—urine, cervicovaginal lavage (CVL), cervical swabs, and external mass and cervical biopsies—alongside provision of detailed demographic information after a thorough medical history questionnaire and an in-depth interview. These samples were screened for the presence of Schistosoma ova on microscopy and DNA genotyping using a novel real-time PCR assay in parallel to pre-published probe-based PCR assays capable of identifying and discriminating up to six named Schistosoma species. A further molecular screen of sexually transmitted infections (STIs) including Trichomonas vaginalis, Chlamydia spp., and human papilloma virus (HPV) was conducted on her genital swab and CVL. Overt FGS was diagnosed on clinical colposcopy alongside inspection of the cervical biopsy by microscopy, real-time PCR, and histopathology. The urine filtration, microscopy and real-time PCR of the CVL and swab were negative. This evidences the typical diagnostic challenge, and cases such as this will pose an unmet need in satisfactory patient management. In addition to Schistosoma haematobium, the presence of the zoonotic species Schistosoma mattheei and concurrent STIs raise questions as to the long-term effectiveness of the current control strategies of the National Control Programme to eliminate schistosomiasis as a public health problem. Improved availability of and regular accessibility to praziquantel treatment for women at risk such as this are urgently needed. Furthermore, targeted health education, increased community awareness, and dovetailing of synergistic activities and strategies with other health stakeholders such as those in sexual and reproductive health, as well as HIV/AIDS programs in the Ministry of Health, are needed here and in neighboring countries.","PeriodicalId":73112,"journal":{"name":"Frontiers in tropical diseases","volume":"99 37","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141359106","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-06DOI: 10.3389/fitd.2024.1353839
S. Leal, Celivianne Marisia Ramos de Sousa, D. Monteiro, Maria da Luz Lima Mendonça, A. Gonçalves, A. DePina
Integrated malaria vector control is crucial to eliminate or reduce infection risk. Understanding vector species distribution, behavior, and environmental factors such as climate, topography, and preferred aquatic habitats is essential.Herein, we aim to compile data from 2016 to 2023 on the primary malaria vector in Cabo Verde to support health surveillance and elimination certification.Mosquitoes larvae were collected using standard sampling tools, and adults using Biogents Sentinel traps, mechanical aspiration and CDC UV light traps, both indoor and in the surroundings of urban and rural areas.Six hundred fifty-seven specimens of Anopheles gambiae s.l. were identified by morphological methods and PCR-based techniques as Anopheles arabiensis in 12 municipalities from six of the nine inhabited islands, namely, São Vicente, São Nicolau, Maio, Boavista, Santiago, and Santo Antão.We believe this is the first scientific report of the presence of An. arabiensis on the island of Santo Antão. The Anopheles arabiensis remains the only species in the An. gambiae complex in the Cabo Verde islands. These results offer vital insights for epidemiological surveillance and effective malaria control, especially in light of the recent WHO certification declaring the country malaria-free. However, it is imperative to conduct further studies that comprehensively address epidemiological and entomological aspects, with a special focus on bionomics, genetic determinants of the parasite-vector association, and the characterization of larval habitats. These investigations have the potential to guide a more informed and strategic implementation of malaria vector control measures in Cabo Verde.
{"title":"The geographical distribution of the malaria vector Anopheles arabiensis in Cabo Verde, 2016–2023","authors":"S. Leal, Celivianne Marisia Ramos de Sousa, D. Monteiro, Maria da Luz Lima Mendonça, A. Gonçalves, A. DePina","doi":"10.3389/fitd.2024.1353839","DOIUrl":"https://doi.org/10.3389/fitd.2024.1353839","url":null,"abstract":"Integrated malaria vector control is crucial to eliminate or reduce infection risk. Understanding vector species distribution, behavior, and environmental factors such as climate, topography, and preferred aquatic habitats is essential.Herein, we aim to compile data from 2016 to 2023 on the primary malaria vector in Cabo Verde to support health surveillance and elimination certification.Mosquitoes larvae were collected using standard sampling tools, and adults using Biogents Sentinel traps, mechanical aspiration and CDC UV light traps, both indoor and in the surroundings of urban and rural areas.Six hundred fifty-seven specimens of Anopheles gambiae s.l. were identified by morphological methods and PCR-based techniques as Anopheles arabiensis in 12 municipalities from six of the nine inhabited islands, namely, São Vicente, São Nicolau, Maio, Boavista, Santiago, and Santo Antão.We believe this is the first scientific report of the presence of An. arabiensis on the island of Santo Antão. The Anopheles arabiensis remains the only species in the An. gambiae complex in the Cabo Verde islands. These results offer vital insights for epidemiological surveillance and effective malaria control, especially in light of the recent WHO certification declaring the country malaria-free. However, it is imperative to conduct further studies that comprehensively address epidemiological and entomological aspects, with a special focus on bionomics, genetic determinants of the parasite-vector association, and the characterization of larval habitats. These investigations have the potential to guide a more informed and strategic implementation of malaria vector control measures in Cabo Verde.","PeriodicalId":73112,"journal":{"name":"Frontiers in tropical diseases","volume":"7 8","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141380583","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-24DOI: 10.3389/fitd.2024.1404634
Janet Masaku, John M. Gachohi, A. Sinkeet, Mary Maghanga, Florence Wakesho, W. Omondi, Lisa Sophie Reigl, Isabelle L. Lange, Andrea S. Winkler, S. Njenga, M. Amuyunzu-Nyamongo
Over 50 million preschool-age children (PSAC) in Africa need treatment for schistosomiasis but are excluded due to lack of a suitable child-friendly medication. The Paediatric Praziquantel Consortium has developed a novel paediatric formulation for PSAC. In advance of its roll-out, we conducted a social science study to draw lessons to inform implementation.We conducted a cross-sectional study in eight villages in two purposively selected highly endemic Kenyan counties (Homa Bay and Kwale). We conducted 17 in-depth interviews with community opinion leaders and 21 with parents/guardians of PSAC. Twelve focus group discussions with parents/guardians of PSAC were also held. The aim was to assess their knowledge, perceptions, practices and willingness to participate in the medication’s roll-out for schistosomiasis. Thematic data analysis was performed.Most participants had heard of schistosomiasis and perceived it to be a serious disease whose treatment should be prioritised. Others felt it was a common disease that should not cause concern. Some people believed schistosomiasis was caused by witchcraft while others regarded it as a sexually transmitted infection. In addition, some practices like poor human waste disposal and water contact were thought to contribute to continued transmission of the disease.Community members know and perceive schistosomiasis to be serious, but misinformation about its cause is prevalent. The study suggests the need for increased awareness creation to change the perceptions of communities in relation to schistosomiasis prevention and control. Community sensitisation should be prioritised in advance of medication roll-out.
{"title":"A qualitative assessment of community perceptions and practices towards schistosomiasis prior to introduction of a potential novel treatment option for preschool-age children in Kenya","authors":"Janet Masaku, John M. Gachohi, A. Sinkeet, Mary Maghanga, Florence Wakesho, W. Omondi, Lisa Sophie Reigl, Isabelle L. Lange, Andrea S. Winkler, S. Njenga, M. Amuyunzu-Nyamongo","doi":"10.3389/fitd.2024.1404634","DOIUrl":"https://doi.org/10.3389/fitd.2024.1404634","url":null,"abstract":"Over 50 million preschool-age children (PSAC) in Africa need treatment for schistosomiasis but are excluded due to lack of a suitable child-friendly medication. The Paediatric Praziquantel Consortium has developed a novel paediatric formulation for PSAC. In advance of its roll-out, we conducted a social science study to draw lessons to inform implementation.We conducted a cross-sectional study in eight villages in two purposively selected highly endemic Kenyan counties (Homa Bay and Kwale). We conducted 17 in-depth interviews with community opinion leaders and 21 with parents/guardians of PSAC. Twelve focus group discussions with parents/guardians of PSAC were also held. The aim was to assess their knowledge, perceptions, practices and willingness to participate in the medication’s roll-out for schistosomiasis. Thematic data analysis was performed.Most participants had heard of schistosomiasis and perceived it to be a serious disease whose treatment should be prioritised. Others felt it was a common disease that should not cause concern. Some people believed schistosomiasis was caused by witchcraft while others regarded it as a sexually transmitted infection. In addition, some practices like poor human waste disposal and water contact were thought to contribute to continued transmission of the disease.Community members know and perceive schistosomiasis to be serious, but misinformation about its cause is prevalent. The study suggests the need for increased awareness creation to change the perceptions of communities in relation to schistosomiasis prevention and control. Community sensitisation should be prioritised in advance of medication roll-out.","PeriodicalId":73112,"journal":{"name":"Frontiers in tropical diseases","volume":"70 13","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141101785","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-23DOI: 10.3389/fitd.2024.1387078
A. Lubanga, A. N. Bwanali, C. Moyo, G. D. Chumbi, Y. Matola, Hyunwook Nam, Lorie Kim, Jooheon Park, Jonathan Chung
{"title":"Beyond RTS,S malaria vaccine piloting to adoption and historic introduction in sub-Saharan Africa: a new hope in the fight against the vector-borne disease","authors":"A. Lubanga, A. N. Bwanali, C. Moyo, G. D. Chumbi, Y. Matola, Hyunwook Nam, Lorie Kim, Jooheon Park, Jonathan Chung","doi":"10.3389/fitd.2024.1387078","DOIUrl":"https://doi.org/10.3389/fitd.2024.1387078","url":null,"abstract":"","PeriodicalId":73112,"journal":{"name":"Frontiers in tropical diseases","volume":"55 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141107164","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-17DOI: 10.3389/fitd.2024.1393570
Swati Sharma, Ujjawal Sharan, Rimanpreet Kaur, Anubha Chaudhary, S. Rawat, Anand K. Keshri, Naina Arora, Amit Prasad
Soil- and water-transmitted helminths are a major concern in the developing world due to their high prevalence. More than a quarter of the population were estimated to be infected with helminths in these endemic zones.An in silico approach was used to design a vaccine construct against the Taenia genus utilizing the proteomic information and evaluation of the construct using immune-informatics.Our study identified 451 conserved proteins in Taenia spp. using the existing proteome; out of these, 141 were found to be expressed in cysticerci. These proteins were screened for antigenic epitopes and a multi-subunit vaccine was constructed. The constructed vaccine was assessed for its efficacy in mounting the appropriate immune response. Our constructed vaccine showed stability and optimal performance against the TLR 4 receptor, which is reported to be upregulated in Taenia infections in hosts.Immune-informatics tools help design vaccines for neglected diseases such as those attributed to helminths, which are known to cause widespread morbidity. Our vaccine construct holds tremendous potential in conferring protection against all Taenia spp. of clinical relevance to human.
{"title":"An inclusive approach to designing a multi-epitope chimeric vaccine for Taenia infections by integrating proteomics and reverse vaccinology","authors":"Swati Sharma, Ujjawal Sharan, Rimanpreet Kaur, Anubha Chaudhary, S. Rawat, Anand K. Keshri, Naina Arora, Amit Prasad","doi":"10.3389/fitd.2024.1393570","DOIUrl":"https://doi.org/10.3389/fitd.2024.1393570","url":null,"abstract":"Soil- and water-transmitted helminths are a major concern in the developing world due to their high prevalence. More than a quarter of the population were estimated to be infected with helminths in these endemic zones.An in silico approach was used to design a vaccine construct against the Taenia genus utilizing the proteomic information and evaluation of the construct using immune-informatics.Our study identified 451 conserved proteins in Taenia spp. using the existing proteome; out of these, 141 were found to be expressed in cysticerci. These proteins were screened for antigenic epitopes and a multi-subunit vaccine was constructed. The constructed vaccine was assessed for its efficacy in mounting the appropriate immune response. Our constructed vaccine showed stability and optimal performance against the TLR 4 receptor, which is reported to be upregulated in Taenia infections in hosts.Immune-informatics tools help design vaccines for neglected diseases such as those attributed to helminths, which are known to cause widespread morbidity. Our vaccine construct holds tremendous potential in conferring protection against all Taenia spp. of clinical relevance to human.","PeriodicalId":73112,"journal":{"name":"Frontiers in tropical diseases","volume":"5 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140965181","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-14DOI: 10.3389/fitd.2024.1371905
R. Mohapatra, Maysoon Al-Haideri, Snehasis Mishra, A. Mahal, Ashish K. Sarangi, M. Khatib, Shilpa Gaidhane, Q. Zahiruddin, A. Mohanty, Ranjit Sah
{"title":"Linking the increasing epidemiology of scrub typhus transmission in India and South Asia: are the varying environment and the reservoir animals the factors behind?","authors":"R. Mohapatra, Maysoon Al-Haideri, Snehasis Mishra, A. Mahal, Ashish K. Sarangi, M. Khatib, Shilpa Gaidhane, Q. Zahiruddin, A. Mohanty, Ranjit Sah","doi":"10.3389/fitd.2024.1371905","DOIUrl":"https://doi.org/10.3389/fitd.2024.1371905","url":null,"abstract":"","PeriodicalId":73112,"journal":{"name":"Frontiers in tropical diseases","volume":"76 19","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140978769","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-13DOI: 10.3389/fitd.2024.1371670
Thierry Rostand Tebo-Nzesseu, Ngouateu Aime Tateng, O. Ngouateu, Cedric Yamssi, N’dille Emmanuel Elanga, C. Ndo, Roland Bamou, Vincent Khan-Payne, B. Dondji
Kousseri in the Far North Region of Cameroon has long been known as an endemic focus of visceral leishmaniasis (VL), although the study on sand flies in this focus is scarce. The present study investigates the spatial distribution, seasonality, and ecological aspects of sand flies from Kousseri. This study is based on the need to optimize the effectiveness of leishmaniasis control programs in the northern part of the country. Sand flies were sampled monthly over 12 months in five selected sites using CDC light traps. Only captured females were morphologically identified at species level based on valid keys. Overall, 4,214 sand fly specimens were collected during 360 trapping nights. The male/female sex ratio slightly favored females (1:1.04). The eudominant Sergentomyia antennata followed by both dominant Sergentomyia schwetzi and Sergentomyia squamipleuris were the most common and abundant species, accounting for 76.1% of the collection. Phlebotomus duboscqi, the confirmed vector of cutaneous leishmaniasis (CL) in West African foci, although rare in the collection, was found in four of the five surveyed sites. This sand fly species with Se. schwetzi abounded in peri-urban areas and, respectively, in animal shed and in uninhabited house biotopes, while Se. antennata and Se. squamipleuris prevailed in rural areas and, respectively, in animal shelter biotopes and outside dwellings. All caught sand fly species except Se. schwetzi, Sergentomyia clydei, Sergentomyia inermis, and Sergentomyia adleri prevailed during the dry season. The highest Shannon–Wiener index of sand flies due to the maximal richness and evenness was found in the urban area, in outdoor biotopes, and during the rainy season (H′ = 1.68, 1.80, and 1.74, respectively). These data provide evidence that less urbanized areas, animal shelters around the compounds, and the absence of precipitation (dry season) favored the dispersion of abundant sand fly species in Kousseri. Based on previous reports on Leishmania transmission, a surveillance plan is required to prevent an outbreak of VL or an establishment of CL or canine leishmaniasis (CnL) in this focus. Further research identifying the blood meal source and the Leishmania parasites in these insects is critical for providing insightful data to fight leishmaniasis in Northern Cameroon.
{"title":"Distribution and ecological aspects of sand fly species from Kousseri, an endemic focus of visceral leishmaniasis in Northern Cameroon","authors":"Thierry Rostand Tebo-Nzesseu, Ngouateu Aime Tateng, O. Ngouateu, Cedric Yamssi, N’dille Emmanuel Elanga, C. Ndo, Roland Bamou, Vincent Khan-Payne, B. Dondji","doi":"10.3389/fitd.2024.1371670","DOIUrl":"https://doi.org/10.3389/fitd.2024.1371670","url":null,"abstract":"Kousseri in the Far North Region of Cameroon has long been known as an endemic focus of visceral leishmaniasis (VL), although the study on sand flies in this focus is scarce. The present study investigates the spatial distribution, seasonality, and ecological aspects of sand flies from Kousseri. This study is based on the need to optimize the effectiveness of leishmaniasis control programs in the northern part of the country. Sand flies were sampled monthly over 12 months in five selected sites using CDC light traps. Only captured females were morphologically identified at species level based on valid keys. Overall, 4,214 sand fly specimens were collected during 360 trapping nights. The male/female sex ratio slightly favored females (1:1.04). The eudominant Sergentomyia antennata followed by both dominant Sergentomyia schwetzi and Sergentomyia squamipleuris were the most common and abundant species, accounting for 76.1% of the collection. Phlebotomus duboscqi, the confirmed vector of cutaneous leishmaniasis (CL) in West African foci, although rare in the collection, was found in four of the five surveyed sites. This sand fly species with Se. schwetzi abounded in peri-urban areas and, respectively, in animal shed and in uninhabited house biotopes, while Se. antennata and Se. squamipleuris prevailed in rural areas and, respectively, in animal shelter biotopes and outside dwellings. All caught sand fly species except Se. schwetzi, Sergentomyia clydei, Sergentomyia inermis, and Sergentomyia adleri prevailed during the dry season. The highest Shannon–Wiener index of sand flies due to the maximal richness and evenness was found in the urban area, in outdoor biotopes, and during the rainy season (H′ = 1.68, 1.80, and 1.74, respectively). These data provide evidence that less urbanized areas, animal shelters around the compounds, and the absence of precipitation (dry season) favored the dispersion of abundant sand fly species in Kousseri. Based on previous reports on Leishmania transmission, a surveillance plan is required to prevent an outbreak of VL or an establishment of CL or canine leishmaniasis (CnL) in this focus. Further research identifying the blood meal source and the Leishmania parasites in these insects is critical for providing insightful data to fight leishmaniasis in Northern Cameroon.","PeriodicalId":73112,"journal":{"name":"Frontiers in tropical diseases","volume":"89 21","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140984585","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-07DOI: 10.3389/fitd.2024.1306429
Kwang Poo Chang, Joseph Reynolds, Dennis K. P. Ng, Yun-Hung Tu, Chia-Kwung Fan, Shin-Hong Shiao
Singlet oxygen (1O2) is a potent biocide potentially deployable for integrated control of tropical diseases and their insect vectors. This very short-lived free radical is highly destructive of cellular molecules when generated intracellularly. Most organisms, including parasites and vectors, are defenseless against 1O2 except for plants, which produce it abundantly during photosynthesis, hence, the acquisition of specific mechanisms for its detoxification. In the presence of O2 under physiological conditions, certain dyes or photosensitizers (PS), e.g., porphyrins and phthalocyanines (PC), are excitable by light to produce biocidal 1O2. Its half-life is in the order of microseconds, necessitating its intracellular generation in order to harness its biocidal activity most effectively. This is achievable by loading cells with PS for excitation with light to produce 1O2in situ. One example to achieve this is the genetic engineering of Leishmania to complement its inherent defects in porphyrin biosynthesis, resulting in cytosolic accumulation of abundant PS in the form of uroporphyrin 1 (URO). Another example is the chemical engineering of PC for hydrophilicity, thereby facilitating the endocytosis of such PS by cells. Leishmania loaded with cytosolic URO and endosomal PC are inactivated by the 1O2 produced via light-activation of these PS in the two different cell compartments. The inactivated Leishmania are nonviable, but have their natural vaccines and adjuvants well-preserved for prophylactic vaccination against experimental leishmaniasis. 1O2-inactivated Leishmania is potentially useful to serve as a platform for the safe and effective delivery of transgenically add-on vaccines against malignant and viral diseases in experimental models. Hydrophilic and cationic PC were also shown experimentally to act as a new type of dim light-activable insecticides, i.e., their mosquito larvicidal activities with <µM LD50 values. Similar results are expected by studying PC in additional laboratory insect models. A significant advantage has long been attributed to this type of insecticide, i.e., their aversion to a selection of genetic variants for resistance. An additional advantage of PC is their excitability to produce insecticidal 1O2 with deep-penetrating red or infrared light invisible to most insects, thereby potentially increasing the range and scope of targetable insect vectors.
{"title":"Molecular approaches to deploy singlet oxygen in a Leishmania model as an unassailable biocide for disease mitigation and vector control","authors":"Kwang Poo Chang, Joseph Reynolds, Dennis K. P. Ng, Yun-Hung Tu, Chia-Kwung Fan, Shin-Hong Shiao","doi":"10.3389/fitd.2024.1306429","DOIUrl":"https://doi.org/10.3389/fitd.2024.1306429","url":null,"abstract":"Singlet oxygen (1O2) is a potent biocide potentially deployable for integrated control of tropical diseases and their insect vectors. This very short-lived free radical is highly destructive of cellular molecules when generated intracellularly. Most organisms, including parasites and vectors, are defenseless against 1O2 except for plants, which produce it abundantly during photosynthesis, hence, the acquisition of specific mechanisms for its detoxification. In the presence of O2 under physiological conditions, certain dyes or photosensitizers (PS), e.g., porphyrins and phthalocyanines (PC), are excitable by light to produce biocidal 1O2. Its half-life is in the order of microseconds, necessitating its intracellular generation in order to harness its biocidal activity most effectively. This is achievable by loading cells with PS for excitation with light to produce 1O2in situ. One example to achieve this is the genetic engineering of Leishmania to complement its inherent defects in porphyrin biosynthesis, resulting in cytosolic accumulation of abundant PS in the form of uroporphyrin 1 (URO). Another example is the chemical engineering of PC for hydrophilicity, thereby facilitating the endocytosis of such PS by cells. Leishmania loaded with cytosolic URO and endosomal PC are inactivated by the 1O2 produced via light-activation of these PS in the two different cell compartments. The inactivated Leishmania are nonviable, but have their natural vaccines and adjuvants well-preserved for prophylactic vaccination against experimental leishmaniasis. 1O2-inactivated Leishmania is potentially useful to serve as a platform for the safe and effective delivery of transgenically add-on vaccines against malignant and viral diseases in experimental models. Hydrophilic and cationic PC were also shown experimentally to act as a new type of dim light-activable insecticides, i.e., their mosquito larvicidal activities with <µM LD50 values. Similar results are expected by studying PC in additional laboratory insect models. A significant advantage has long been attributed to this type of insecticide, i.e., their aversion to a selection of genetic variants for resistance. An additional advantage of PC is their excitability to produce insecticidal 1O2 with deep-penetrating red or infrared light invisible to most insects, thereby potentially increasing the range and scope of targetable insect vectors.","PeriodicalId":73112,"journal":{"name":"Frontiers in tropical diseases","volume":"95 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141004206","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-02DOI: 10.3389/fitd.2024.1386668
E. Kenu, D. Bandoh, B. B. Kaburi, Joyce Berkumwin Der
{"title":"Editorial: Public health surveillance systems and outbreak response: evidence from the field","authors":"E. Kenu, D. Bandoh, B. B. Kaburi, Joyce Berkumwin Der","doi":"10.3389/fitd.2024.1386668","DOIUrl":"https://doi.org/10.3389/fitd.2024.1386668","url":null,"abstract":"","PeriodicalId":73112,"journal":{"name":"Frontiers in tropical diseases","volume":"37 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141022619","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-01DOI: 10.3389/fitd.2024.1308585
Joshua R. Lacsina, Ryan Kissinger, Johannes S. P. Doehl, Maria Disotuar, George Petrellis, Mara Short, Elliot Lowe, James Oristian, Daniel Sonenshine, Thiago DeSouza-Vieira
Infections caused by vector-borne pathogens impose a significant burden of morbidity and mortality in a global scale. In their quest for blood, hematophagous arthropods penetrate the host skin and may transmit pathogens by the bite. These pathogens are deposited along with saliva and a complex mixture of vector derived factors. Hematophagous arthopod vectors have evolved a complex array of adaptations to modulate the host immune response at the bite site with the primary goal to improve blood feeding, which have been exploited throughout evolution by these pathogens to enhance infection establishment in the host. While this paradigm has been firmly established in mouse models, comparable data from human studies are scarce. Here we review how the host skin immune response to vector bites in animal models is hijacked by microbes to promote their pathogenesis. We mainly explored four distinct vector-pathogen pairs of global health importance: sand flies and Leishmania parasites, Ixodes scapularis ticks and Borrelia burgdorferi, Aedes aegypti mosquitoes and arboviruses, and Anopheles gambiae mosquitos and Plasmodium parasites. Finally, we outline how critical it is for the field of vector biology to shift from rodent models to clinical studies focused on the interface of vector-pathogen-host immune system to push further the frontiers of knowledge of the field.
{"title":"Host skin immunity to arthropod vector bites: from mice to humans","authors":"Joshua R. Lacsina, Ryan Kissinger, Johannes S. P. Doehl, Maria Disotuar, George Petrellis, Mara Short, Elliot Lowe, James Oristian, Daniel Sonenshine, Thiago DeSouza-Vieira","doi":"10.3389/fitd.2024.1308585","DOIUrl":"https://doi.org/10.3389/fitd.2024.1308585","url":null,"abstract":"Infections caused by vector-borne pathogens impose a significant burden of morbidity and mortality in a global scale. In their quest for blood, hematophagous arthropods penetrate the host skin and may transmit pathogens by the bite. These pathogens are deposited along with saliva and a complex mixture of vector derived factors. Hematophagous arthopod vectors have evolved a complex array of adaptations to modulate the host immune response at the bite site with the primary goal to improve blood feeding, which have been exploited throughout evolution by these pathogens to enhance infection establishment in the host. While this paradigm has been firmly established in mouse models, comparable data from human studies are scarce. Here we review how the host skin immune response to vector bites in animal models is hijacked by microbes to promote their pathogenesis. We mainly explored four distinct vector-pathogen pairs of global health importance: sand flies and Leishmania parasites, Ixodes scapularis ticks and Borrelia burgdorferi, Aedes aegypti mosquitoes and arboviruses, and Anopheles gambiae mosquitos and Plasmodium parasites. Finally, we outline how critical it is for the field of vector biology to shift from rodent models to clinical studies focused on the interface of vector-pathogen-host immune system to push further the frontiers of knowledge of the field.","PeriodicalId":73112,"journal":{"name":"Frontiers in tropical diseases","volume":"84 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141050581","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}