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Ghakanyuy BM, Teboh-Ewungkem MI, Schneider KA, Ngwa GA. Investigating the impact of multiple feeding attempts on mosquito dynamics via mathematical models. Math Biosci 2022; 350:108832. [PMID: 35718220 DOI: 10.1016/j.mbs.2022.108832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 04/07/2022] [Accepted: 05/09/2022] [Indexed: 11/27/2022]
Abstract
A deterministic differential equation model for the dynamics of terrestrial forms of mosquito populations is studied. The model assesses the impact of multiple probing attempts by mosquitoes that quest for blood within human populations by including a waiting class for mosquitoes that failed a blood feeding attempt. The equations are derived based on the idea that the reproductive cycle of the mosquito can be viewed as a set of alternating egg laying and blood feeding outcomes realized on a directed path called the gonotrophic cycle pathway. There exists a threshold parameter, the basic offspring number for mosquitoes, whose nature is affected by the way we interpret the transitions involving the different classes on the gonotrophic cycle path. The trivial steady state for the system, which always exists, can be globally asymptomatically stable whenever the threshold parameter is less than unity. The non-trivial steady state, when it exists, is stable for a range of values of the threshold parameter but can also be driven to instability via a Hopf bifurcation. The model's output reveals that the waiting class mosquitoes do contribute positively to sustain mosquito populations as well as increase their interactions with humans via increased frequency and initial amplitude of oscillations. We conclude that to understand human-mosquito interactions, it is informative to consider multiple probing attempts; known to occur when mosquitoes quest for blood meals within human populations.
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Affiliation(s)
- Bime M Ghakanyuy
- Department of Mathematics, University of Buea, P.O. Box 63, Buea, Cameroon
| | | | - Kristan A Schneider
- Department of Applied Computer and Bio-Sciences, University of Applied Sciences, Mittweida, Technikumplatz 17, 09648 Mittweida, Germany
| | - Gideon A Ngwa
- Department of Mathematics, University of Buea, P.O. Box 63, Buea, Cameroon.
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Lin LY, Li J, Huang HY, Liang XY, Jiang TT, Chen JT, Ehapo CS, Eyi UM, Zheng YZ, Zha GC, Xie DD, Wang YL, Chen WZ, Liu XZ, Lin M. Trends in Molecular Markers Associated with Resistance to Sulfadoxine-Pyrimethamine (SP) Among Plasmodium falciparum Isolates on Bioko Island, Equatorial Guinea: 2011-2017. Infect Drug Resist 2020; 13:1203-1212. [PMID: 32431521 PMCID: PMC7197940 DOI: 10.2147/idr.s236898] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Accepted: 03/19/2020] [Indexed: 02/05/2023] Open
Abstract
PURPOSE Antimalarial drug resistance is one of the major challenges in global efforts to control and eliminate malaria. In 2006, sulfadoxine-pyrimethamine (SP) replaced with artemisinin-based combination therapy (ACT) on Bioko Island, Equatorial Guinea, in response to increasing SP resistance, which is associated with mutations in the dihydrofolate reductase (Pfdhfr) and dihydropteroate synthase (Pfdhps) genes. PATIENTS AND METHODS To evaluate the trend of molecular markers associated with SP resistance on Bioko Island from 2011 to 2017, 179 samples collected during active case detection were analysed by PCR and DNA sequencing. RESULTS Pfdhfr and Pfdhps gene sequences were obtained for 90.5% (162/179) and 77.1% (138/179) of the samples, respectively. For Pfdhfr, 97.5% (158/162), 95.7% (155/162) and 98.1% (159/162) of the samples contained N51I, C59R and S108N mutant alleles, respectively. And Pfdhps S436A, A437G, K540E, A581G, and A613S mutations were observed in 25.4% (35/138), 88.4% (122/138), 5.1% (7/138), 1.4% (2/138), and 7.2% (10/138) of the samples, respectively. Two classes of previously described Pfdhfr-Pfdhps haplotypes associated with SP resistance and their frequencies were identified: partial (IRNI-SGKAA, 59.4%) and full (IRNI-SGEAA, 5.5%) resistance. Although no significant difference was observed in different time periods (p>0.05), our study confirmed a slowly increasing trend of the frequencies of these SP-resistance markers in Bioko parasites over the 7 years investigated. CONCLUSION The findings reveal the general existence of SP-resistance markers on Bioko Island even after the replacement of SP as a first-line treatment for uncomplicated malaria. Continuous molecular monitoring and additional control efforts in the region are urgently needed.
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Affiliation(s)
- Li-Yun Lin
- School of Food Engineering and Biotechnology, Hanshan Normal University, Chaozhou, Guangdong Province, People’s Republic of China
- University of Chinese Academy of Sciences, Beijing, People’s Republic of China
- CAS Key Laboratory of Tropical Marine Bio-Resources and Ecology, Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, People’s Republic of China
| | - Jian Li
- Department of Human Parasitology, School of Basic Medical Sciences; Department of Infectious Diseases, Renmin Hospital, Hubei University of Medicine, Shiyan, Hubei Province, People’s Republic of China
| | - Hui-Ying Huang
- Department of Medical Laboratory, Chaozhou People’s Hospital Affiliated to Shantou University Medical College, Chaozhou, Guangdong Province, People’s Republic of China
- Department of Medical Genetics, Shantou University Medical College, Shantou, Guangdong Province, People’s Republic of China
| | - Xue-Yan Liang
- Department of Medical Laboratory, Chaozhou People’s Hospital Affiliated to Shantou University Medical College, Chaozhou, Guangdong Province, People’s Republic of China
- Department of Medical Genetics, Shantou University Medical College, Shantou, Guangdong Province, People’s Republic of China
| | - Ting-Ting Jiang
- Department of Human Parasitology, School of Basic Medical Sciences; Department of Infectious Diseases, Renmin Hospital, Hubei University of Medicine, Shiyan, Hubei Province, People’s Republic of China
| | - Jiang-Tao Chen
- The Chinese Medical Aid Team to the Republic of Equatorial Guinea, Guangzhou, Guangdong Province, People’s Republic of China
- Department of Medical Laboratory, Huizhou Central Hospital, Huizhou, Guangdong Province, People’s Republic of China
| | - Carlos Salas Ehapo
- Department of Medical Laboratory, Malabo Regional Hospital, Malabo, Equatorial Guinea
| | - Urbano Monsuy Eyi
- Department of Medical Laboratory, Malabo Regional Hospital, Malabo, Equatorial Guinea
| | - Yu-Zhong Zheng
- School of Food Engineering and Biotechnology, Hanshan Normal University, Chaozhou, Guangdong Province, People’s Republic of China
| | - Guang-Cai Zha
- School of Food Engineering and Biotechnology, Hanshan Normal University, Chaozhou, Guangdong Province, People’s Republic of China
| | - Dong-De Xie
- The Chinese Medical Aid Team to the Republic of Equatorial Guinea, Guangzhou, Guangdong Province, People’s Republic of China
- Department of Medical Laboratory, Huizhou Central Hospital, Huizhou, Guangdong Province, People’s Republic of China
| | - Yu-Ling Wang
- The Chinese Medical Aid Team to the Republic of Equatorial Guinea, Guangzhou, Guangdong Province, People’s Republic of China
- Department of Medical Laboratory, Huizhou Central Hospital, Huizhou, Guangdong Province, People’s Republic of China
| | - Wei-Zhong Chen
- Department of Medical Laboratory, Chaozhou People’s Hospital Affiliated to Shantou University Medical College, Chaozhou, Guangdong Province, People’s Republic of China
- Department of Medical Genetics, Shantou University Medical College, Shantou, Guangdong Province, People’s Republic of China
| | - Xiang-Zhi Liu
- Department of Medical Laboratory, Chaozhou People’s Hospital Affiliated to Shantou University Medical College, Chaozhou, Guangdong Province, People’s Republic of China
- Department of Medical Genetics, Shantou University Medical College, Shantou, Guangdong Province, People’s Republic of China
| | - Min Lin
- School of Food Engineering and Biotechnology, Hanshan Normal University, Chaozhou, Guangdong Province, People’s Republic of China
- Department of Medical Laboratory, Chaozhou People’s Hospital Affiliated to Shantou University Medical College, Chaozhou, Guangdong Province, People’s Republic of China
- Department of Medical Genetics, Shantou University Medical College, Shantou, Guangdong Province, People’s Republic of China
- Correspondence: Min Lin School of Food Engineering and Biotechnology, Hanshan Normal University, Chaozhou, Guangdong Province, People’s Republic of China Tel/Fax +86 768-2317422 Email
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