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  1. Article ; Online: The role of the major chemosensory organs in the host-seeking activity of Anopheles coluzzii (Diptera: Culicidae).

    Popkin-Hall, Zachary R / Slotman, Michel A

    Journal of medical entomology

    2024  

    Abstract: Anopheles coluzzii (Coetzee & Wilkerson) and its sibling species Anopheles gambiae s.s. (Giles) are highly anthropophilic and among the major malaria vectors in sub-Saharan Africa. Mosquitoes use various senses to find hosts, but rely primarily on ... ...

    Abstract Anopheles coluzzii (Coetzee & Wilkerson) and its sibling species Anopheles gambiae s.s. (Giles) are highly anthropophilic and among the major malaria vectors in sub-Saharan Africa. Mosquitoes use various senses to find hosts, but rely primarily on olfaction. Therefore, the mosquito olfactory system has been studied extensively, including a variety of studies comparing chemosensory gene expression between An. coluzzii and its zoophilic sibling species Anopheles quadriannulatus (Theobald). These studies revealed species-specific chemosensory gene expression in the antennae and maxillary palps, which raised the question of a potential role for the palps in determining species-specific host preferences. To answer this question, we mechanically ablated the antennae, maxillary palps, and labella, and ran both control and ablated mosquitoes through a dual-port olfactometer. While we aimed to identify the organs responsible for vertebrate host choice, the ablated mosquitoes exclusively responded to human odor, so we were unable to do so. However, we were able to refine our understanding of the roles of these organs in host-seeking activation (leaving the release cage) as well as odor response (entering an odor port). As expected, the antennae are the most important organs to both behaviors: activation was roughly halved and vertebrate odor response was abolished in antennae-ablated mosquitoes. Maxillary palp ablation had little impact on activation, but reduced odor response to a similar degree as the exclusion of CO2. Finally, while labellar ablation dramatically reduced activation (probably associated with the inability to feed), it had little impact on odor response, suggesting that any labellar role in host choice is likely not olfactory.
    Language English
    Publishing date 2024-05-11
    Publishing country England
    Document type Journal Article
    ZDB-ID 410635-0
    ISSN 1938-2928 ; 0022-2585
    ISSN (online) 1938-2928
    ISSN 0022-2585
    DOI 10.1093/jme/tjae062
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article ; Online: The Expression of Chemosensory Genes in Male Maxillary Palps of Anopheles coluzzii (Diptera: Culicidae) and An. quadriannulatus.

    Athrey, Giridhar / Popkin-Hall, Zachary R / Takken, Willem / Slotman, Michel A

    Journal of medical entomology

    2021  Volume 58, Issue 3, Page(s) 1012–1020

    Abstract: Because of its importance as a malaria vector, Anopheles coluzzii's Coetzee & Wilkerson olfactory system has been studied extensively. Among this work is a series of studies comparing the expression of chemosensory genes in olfactory organs in females ... ...

    Abstract Because of its importance as a malaria vector, Anopheles coluzzii's Coetzee & Wilkerson olfactory system has been studied extensively. Among this work is a series of studies comparing the expression of chemosensory genes in olfactory organs in females and/or males of these species. These have identified species- and female-biased chemosensory gene expression patterns. However, many questions remain about the role of chemosensation in male anopheline biology. To pave the way for future work we used RNAseq to compare chemosensory gene expression in the male maxillary palps of An. coluzzii and its sibling species An. quadriannulatus Theobald. As expected, the chemosensory gene repertoire is small in the male maxillary palps. Both species express the tuning receptors Or8 and Or28 at relatively high levels. The CO2 receptor genes Gr22-Gr24 are present in both species as well, although at much lower level than in females. Additionally, several chemoreceptors are species-specific. Gr37 and Gr52 are exclusive to An. coluzzii, whereas Or9 and Gr60 were detected only in An. quadriannulatus. Furthermore, several chemosensory genes show differential expression between the two species. Finally, several Irs, Grs, and Obps that show strong differential expression in the female palps, are absent or lowly expressed in the male palps. While many questions remain about the role of chemosensation in anopheline male biology, these results suggest that the male maxillary palps could have both a sex- and species-specific role in the perception of chemical stimuli. This work may guide future studies on the role of the male maxillary palp in these species.
    MeSH term(s) Animals ; Anopheles/genetics ; Anopheles/metabolism ; Chemoreceptor Cells/metabolism ; Gene Expression ; Insect Proteins/genetics ; Insect Proteins/metabolism ; Male ; Mouth ; Species Specificity
    Chemical Substances Insect Proteins
    Language English
    Publishing date 2021-02-12
    Publishing country England
    Document type Journal Article ; Research Support, N.I.H., Extramural
    ZDB-ID 410635-0
    ISSN 1938-2928 ; 0022-2585
    ISSN (online) 1938-2928
    ISSN 0022-2585
    DOI 10.1093/jme/tjaa290
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article: The Expression of Chemosensory Genes in Male Maxillary Palps of Anopheles coluzzii (Diptera: Culicidae) and An. quadriannulatus

    Athrey, Giridhar / Popkin-Hall, Zachary R / Takken, Willem / Slotman, Michel A

    Journal of medical entomology. 2021 Feb. 12, v. 58, no. 3

    2021  

    Abstract: Because of its importance as a malaria vector, Anopheles coluzzii's Coetzee & Wilkerson olfactory system has been studied extensively. Among this work is a series of studies comparing the expression of chemosensory genes in olfactory organs in females ... ...

    Abstract Because of its importance as a malaria vector, Anopheles coluzzii's Coetzee & Wilkerson olfactory system has been studied extensively. Among this work is a series of studies comparing the expression of chemosensory genes in olfactory organs in females and/or males of these species. These have identified species- and female-biased chemosensory gene expression patterns. However, many questions remain about the role of chemosensation in male anopheline biology. To pave the way for future work we used RNAseq to compare chemosensory gene expression in the male maxillary palps of An. coluzzii and its sibling species An. quadriannulatus Theobald. As expected, the chemosensory gene repertoire is small in the male maxillary palps. Both species express the tuning receptors Or8 and Or28 at relatively high levels. The CO₂ receptor genes Gr22-Gr24 are present in both species as well, although at much lower level than in females. Additionally, several chemoreceptors are species-specific. Gr37 and Gr52 are exclusive to An. coluzzii, whereas Or9 and Gr60 were detected only in An. quadriannulatus. Furthermore, several chemosensory genes show differential expression between the two species. Finally, several Irs, Grs, and Obps that show strong differential expression in the female palps, are absent or lowly expressed in the male palps. While many questions remain about the role of chemosensation in anopheline male biology, these results suggest that the male maxillary palps could have both a sex- and species-specific role in the perception of chemical stimuli. This work may guide future studies on the role of the male maxillary palp in these species.
    Keywords Anopheles gambiae ; carbon dioxide ; chemoreceptors ; females ; gene expression ; gene expression regulation ; genes ; males ; medical entomology ; mosquito vectors ; palps ; sibling species
    Language English
    Dates of publication 2021-0212
    Size p. 1012-1020.
    Publishing place Entomological Society of America
    Document type Article
    Note NAL-AP-2-clean
    ZDB-ID 410635-0
    ISSN 0022-2585
    ISSN 0022-2585
    DOI 10.1093/jme/tjaa290
    Database NAL-Catalogue (AGRICOLA)

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  4. Article: Genetic polymorphism and evidence of signatures of selection in the

    Lyimo, Beatus M / Bakari, Catherine / Popkin-Hall, Zachary R / Giesbrecht, David J / Seth, Misago D / Pereus, Dativa / Moshi, Ramadhan / Boniface, Ruth / Mandara, Celine I / Madebe, Rashid / Juliano, Jonathan J / Bailey, Jeffrey A / Ishengoma, Deus S

    medRxiv : the preprint server for health sciences

    2024  

    Abstract: Background: In 2021 and 2023, the World Health Organization approved RTS, S/AS01 and R21/Matrix M malaria vaccines, respectively, for routine immunization of children in African countries with moderate to high transmission. These vaccines are made of !## ...

    Abstract Background: In 2021 and 2023, the World Health Organization approved RTS, S/AS01 and R21/Matrix M malaria vaccines, respectively, for routine immunization of children in African countries with moderate to high transmission. These vaccines are made of
    Methods: The analysis involved 589 whole genome sequences generated by and as part of the MalariaGEN Community Project. The samples were collected between 2013 and January 2015 from five regions of mainland Tanzania: Morogoro and Tanga (Muheza) (moderate transmission areas), and Kagera (Muleba), Lindi (Nachingwea), and Kigoma (Ujiji) (high transmission areas). Wright's inbreeding coefficient (F
    Results: Based on F
    Conclusions: The findings demonstrate high diversity of the
    Language English
    Publishing date 2024-01-23
    Publishing country United States
    Document type Preprint
    DOI 10.1101/2024.01.23.24301587
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article ; Online: Evaluation of Malaria Rapid Diagnostic Test Performance and pfhrp2 Deletion in Tanzania School Surveys, 2017.

    Ngasala, Billy / Chacky, Frank / Mohamed, Ally / Molteni, Fabrizio / Nyinondi, Ssanyu / Kabula, Bilali / Mkali, Humphrey / Thwai, Kyaw / Popkin-Hall, Zachary R / Mitchell, Cedar / Parr, Jonathan B / Juliano, Jonathan J / Lin, Jessica T

    The American journal of tropical medicine and hygiene

    2024  Volume 110, Issue 5, Page(s) 887–891

    Abstract: As part of malaria nationwide monitoring and evaluation initiatives, there is an increasing trend of incorporating malaria rapid diagnostic tests (mRDTs) in surveys conducted within primary schools to detect malaria parasites. However, mRDTs based on the ...

    Abstract As part of malaria nationwide monitoring and evaluation initiatives, there is an increasing trend of incorporating malaria rapid diagnostic tests (mRDTs) in surveys conducted within primary schools to detect malaria parasites. However, mRDTs based on the detection of histidine-rich protein 2 (HRP2) are known to yield false-positive results due to persistent antigenemia, and false-negative results may result from low parasitemia or Plasmodium falciparum hrp2/3 gene deletion. We evaluated diagnostic performance of an HRP2 and pan-parasite lactate dehydrogenase (HRP2/pLDH) mRDT against polymerase chain reaction (PCR) for detection of P. falciparum among 17,051 primary school-age children from eight regions of Tanzania in 2017. According to PCR, the prevalence of P. falciparum was 19.2% (95% CI: 18.6-19.8). Using PCR as reference, the sensitivity and specificity of mRDT was 76.2% (95% CI: 74.7-77.7) and 93.9% (95% CI: 93.5-94.3), respectively. Test agreement was lowest in low transmission areas, where true-positive mRDTs were outnumbered by false-negatives due to low parasitemia. Discordant samples (mRDT-negative but PCR-positive) were screened for pfhrp2/3 deletion by real-time PCR. Among those with a parasite density sufficient for analysis, pfhrp2 deletion was confirmed in 60 samples, whereas pfhrp3 deletion was confirmed in two samples; one sample had both pfhrp2 and pfhrp3 deletions. The majority of samples with gene deletions were detected in the high-transmission Kagera region. Compared with mRDTs, PCR and other molecular methods offer increased sensitivity and are not affected by pfhrp2/3 deletions, making them a useful supplement to mRDTs in schools and other epidemiological surveys.
    MeSH term(s) Tanzania/epidemiology ; Humans ; Antigens, Protozoan/genetics ; Malaria, Falciparum/diagnosis ; Malaria, Falciparum/epidemiology ; Protozoan Proteins/genetics ; Child ; Plasmodium falciparum/genetics ; Plasmodium falciparum/isolation & purification ; Diagnostic Tests, Routine/methods ; Sensitivity and Specificity ; Gene Deletion ; Female ; Male ; Schools ; Polymerase Chain Reaction/methods ; Prevalence ; Rapid Diagnostic Tests
    Chemical Substances HRP-2 antigen, Plasmodium falciparum ; Antigens, Protozoan ; Protozoan Proteins
    Language English
    Publishing date 2024-03-19
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 2942-7
    ISSN 1476-1645 ; 0002-9637
    ISSN (online) 1476-1645
    ISSN 0002-9637
    DOI 10.4269/ajtmh.23-0771
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  6. Article ; Online: The Expression of Chemosensory Genes in Male Maxillary Palps of Anopheles coluzzii (Diptera:Culicidae) and An. quadriannulatus

    Athrey, Giridhar / Popkin-Hall, Zachary R. / Takken, Willem / Slotman, Michel A.

    Journal of Medical Entomology

    2021  Volume 58, Issue 3

    Abstract: Because of its importance as a malaria vector, Anopheles coluzzii's Coetzee & Wilkerson olfactory system has been studied extensively. Among this work is a series of studies comparing the expression of chemosensory genes in olfactory organs in females ... ...

    Abstract Because of its importance as a malaria vector, Anopheles coluzzii's Coetzee & Wilkerson olfactory system has been studied extensively. Among this work is a series of studies comparing the expression of chemosensory genes in olfactory organs in females and/or males of these species. These have identified species- and female-biased chemosensory gene expression patterns. However, many questions remain about the role of chemosensation in male anopheline biology. To pave the way for future work we used RNAseq to compare chemosensory gene expression in the male maxillary palps of An. coluzzii and its sibling species An. quadriannulatus Theobald. As expected, the chemosensory gene repertoire is small in the male maxillary palps. Both species express the tuning receptors Or8 and Or28 at relatively high levels. The CO2 receptor genes Gr22-Gr24 are present in both species as well, although at much lower level than in females. Additionally, several chemoreceptors are species-specific. Gr37 and Gr52 are exclusive to An. coluzzii, whereas Or9 and Gr60 were detected only in An. quadriannulatus. Furthermore, several chemosensory genes show differential expression between the two species. Finally, several Irs, Grs, and Obps that show strong differential expression in the female palps, are absent or lowly expressed in the male palps. While many questions remain about the role of chemosensation in anopheline male biology, these results suggest that the male maxillary palps could have both a sex- and species-specific role in the perception of chemical stimuli. This work may guide future studies on the role of the male maxillary palp in these species.
    Keywords chemosensory gene ; malaria vector ; male behavior ; maxillary palp
    Subject code 590
    Language English
    Publishing country nl
    Document type Article ; Online
    ZDB-ID 410635-0
    ISSN 0022-2585
    ISSN 0022-2585
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  7. Article ; Online: Prevalence of non-falciparum malaria infections among asymptomatic individuals in four regions of Mainland Tanzania.

    Popkin-Hall, Zachary R / Seth, Misago D / Madebe, Rashid A / Budodo, Rule / Bakari, Catherine / Francis, Filbert / Pereus, Dativa / Giesbrecht, David J / Mandara, Celine I / Mbwambo, Daniel / Aaron, Sijenunu / Lusasi, Abdallah / Lazaro, Samwel / Bailey, Jeffrey A / Juliano, Jonathan J / Gutman, Julie R / Ishengoma, Deus S

    Parasites & vectors

    2024  Volume 17, Issue 1, Page(s) 153

    Abstract: Background: Recent studies point to the need to incorporate the detection of non-falciparum species into malaria surveillance activities in sub-Saharan Africa, where 95% of the world's malaria cases occur. Although malaria caused by infection with ... ...

    Abstract Background: Recent studies point to the need to incorporate the detection of non-falciparum species into malaria surveillance activities in sub-Saharan Africa, where 95% of the world's malaria cases occur. Although malaria caused by infection with Plasmodium falciparum is typically more severe than malaria caused by the non-falciparum Plasmodium species P. malariae, P. ovale spp. and P. vivax, the latter may be more challenging to diagnose, treat, control and ultimately eliminate. The prevalence of non-falciparum species throughout sub-Saharan Africa is poorly defined. Tanzania has geographical heterogeneity in transmission levels but an overall high malaria burden.
    Methods: To estimate the prevalence of malaria species in Mainland Tanzania, we randomly selected 1428 samples from 6005 asymptomatic isolates collected in previous cross-sectional community surveys across four regions and analyzed these by quantitative PCR to detect and identify the Plasmodium species.
    Results: Plasmodium falciparum was the most prevalent species in all samples, with P. malariae and P. ovale spp. detected at a lower prevalence (< 5%) in all four regions; P. vivax was not detected in any sample.
    Conclusions: The results of this study indicate that malaria elimination efforts in Tanzania will need to account for and enhance surveillance of these non-falciparum species.
    MeSH term(s) Humans ; Asymptomatic Infections/epidemiology ; Cross-Sectional Studies ; Malaria/epidemiology ; Malaria, Falciparum/epidemiology ; Malaria, Vivax/epidemiology ; Plasmodium falciparum ; Plasmodium malariae ; Prevalence ; Tanzania/epidemiology
    Language English
    Publishing date 2024-03-23
    Publishing country England
    Document type Journal Article
    ZDB-ID 2409480-8
    ISSN 1756-3305 ; 1756-3305
    ISSN (online) 1756-3305
    ISSN 1756-3305
    DOI 10.1186/s13071-024-06242-4
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  8. Article ; Online: Genetic polymorphism and evidence of signatures of selection in the Plasmodium falciparum circumsporozoite protein gene in Tanzanian regions with different malaria endemicity.

    Lyimo, Beatus M / Bakari, Catherine / Popkin-Hall, Zachary R / Giesbrecht, David J / Seth, Misago D / Pereus, Dativa / Shabani, Zulfa I / Moshi, Ramadhan / Boniface, Ruth / Mandara, Celine I / Madebe, Rashid / Juliano, Jonathan J / Bailey, Jeffrey A / Ishengoma, Deus S

    Malaria journal

    2024  Volume 23, Issue 1, Page(s) 139

    Abstract: Background: In 2021 and 2023, the World Health Organization approved RTS,S/AS01 and R21/Matrix M malaria vaccines, respectively, for routine immunization of children in African countries with moderate to high transmission. These vaccines are made of ... ...

    Abstract Background: In 2021 and 2023, the World Health Organization approved RTS,S/AS01 and R21/Matrix M malaria vaccines, respectively, for routine immunization of children in African countries with moderate to high transmission. These vaccines are made of Plasmodium falciparum circumsporozoite protein (PfCSP), but polymorphisms in the gene raise concerns regarding strain-specific responses and the long-term efficacy of these vaccines. This study assessed the Pfcsp genetic diversity, population structure and signatures of selection among parasites from areas of different malaria transmission intensities in Mainland Tanzania, to generate baseline data before the introduction of the malaria vaccines in the country.
    Methods: The analysis involved 589 whole genome sequences generated by and as part of the MalariaGEN Community Project. The samples were collected between 2013 and January 2015 from five regions of Mainland Tanzania: Morogoro and Tanga (Muheza) (moderate transmission areas), and Kagera (Muleba), Lindi (Nachingwea), and Kigoma (Ujiji) (high transmission areas). Wright's inbreeding coefficient (F
    Results: Based on F
    Conclusions: The findings demonstrate high diversity of the Pfcsp gene with limited population differentiation. The Pfcsp gene showed positive Tajima's D values, consistent with balancing selection for variants within Th2R and Th3R regions. The study observed differences between the intended haplotypes incorporated into the design of RTS,S and R21 vaccines and those present in natural parasite populations. Therefore, additional research is warranted, incorporating other regions and more recent data to comprehensively assess trends in genetic diversity within this important gene. Such insights will inform the choice of alleles to be included in the future vaccines.
    MeSH term(s) Humans ; Endemic Diseases ; Malaria, Falciparum/parasitology ; Plasmodium falciparum/genetics ; Polymorphism, Genetic ; Protozoan Proteins/genetics ; Selection, Genetic ; Tanzania
    Chemical Substances circumsporozoite protein, Protozoan ; Protozoan Proteins
    Language English
    Publishing date 2024-05-08
    Publishing country England
    Document type Journal Article
    ZDB-ID 2091229-8
    ISSN 1475-2875 ; 1475-2875
    ISSN (online) 1475-2875
    ISSN 1475-2875
    DOI 10.1186/s12936-024-04974-3
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  9. Article: Strong isolation by distance and evidence of population microstructure reflect ongoing

    Connelly, Sean V / Brazeau, Nicholas F / Msellem, Mwinyi / Ngasala, Billy E / Aydemir, Özkan / Goel, Varun / Niaré, Karamoko / Giesbrecht, David J / Popkin-Hall, Zachary R / Hennelly, Christopher M / Park, Zackary / Moormann, Ann M / Ong'echa, John Michael / Verity, Robert / Mohammed, Safia / Shija, Shija J / Mhamilawa, Lwidiko E / Morris, Ulrika / Mårtensson, Andreas /
    Lin, Jessica T / Björkman, Anders / Juliano, Jonathan J / Bailey, Jeffrey A

    medRxiv : the preprint server for health sciences

    2024  

    Abstract: The Zanzibar archipelago of Tanzania has become a low-transmission area ... ...

    Abstract The Zanzibar archipelago of Tanzania has become a low-transmission area for
    Language English
    Publishing date 2024-02-13
    Publishing country United States
    Document type Preprint
    DOI 10.1101/2023.02.15.23285960
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  10. Article: Malaria species prevalence among asymptomatic individuals in four regions of Mainland Tanzania.

    Popkin Hall, Zachary R / Seth, Misago D / Madebe, Rashid A / Budodo, Rule / Bakari, Catherine / Francis, Filbert / Pereus, Dativa / Giesbrecht, David J / Mandara, Celine I / Mbwambo, Daniel / Aaron, Sijenunu / Lusasi, Abdallah / Lazaro, Samwel / Bailey, Jeffrey A / Juliano, Jonathan J / Gutman, Julie R / Ishengoma, Deus S

    medRxiv : the preprint server for health sciences

    2023  

    Abstract: Recent studies point to the need to incorporate non-falciparum species detection into malaria surveillance activities in sub-Saharan Africa, where 95% of malaria cases occur. ... ...

    Abstract Recent studies point to the need to incorporate non-falciparum species detection into malaria surveillance activities in sub-Saharan Africa, where 95% of malaria cases occur. Although
    Language English
    Publishing date 2023-12-30
    Publishing country United States
    Document type Preprint
    DOI 10.1101/2023.12.28.23300584
    Database MEDical Literature Analysis and Retrieval System OnLINE

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