Malaria Incidence Among Oil/Gas Workers After Three Years of Indoor Residual Spraying (IRS) and two of Improved Case Management on Bioko Island, Equatorial Guinea (EG)

2008 ◽  
Author(s):  
Luis E. Benavente ◽  
Brian Linder ◽  
Immo Kleinschmidt
Keyword(s):  
Case Management ◽  
Malaria Incidence ◽  
Indoor Residual Spraying ◽  
Equatorial Guinea ◽  
Bioko Island ◽  
Oil Gas

scholarly journals A Colorimetric Test for the Evaluation of the Insecticide Content of LLINs Used on Bioko Island, Equatorial Guinea

2020 ◽  
Author(s):  
Harparkash Kaur ◽  
Elizabeth Louise Allan ◽  
Teunis A Eggelte ◽  
Guillermo A Garcia ◽  
Feliciano Monti
Keyword(s):  
Indoor Residual Spraying ◽  
World Health ◽  
Equatorial Guinea ◽  
Bed Nets ◽  
Type Ii ◽  
Insecticide Treated Nets ◽  
Bioko Island ◽  
Colorimetric Test ◽  
Test Kit

Abstract BackgroundInsecticide-treated nets and indoor residual spraying of insecticides are used as the major vector control interventions in the fight against malaria. Measuring the actual amount of deposits of insecticides on bed nets and walls is essential for evaluating the quality and effectiveness of the intervention. A colorimetric “Test Kit” designed for use as a screening tool, able to detect the type II pyrethroids on fabrics and sprayed walls, was used for the first time to detect deltamethrin on long-lasting insecticidal nets (LLINs) deployed on Bioko Island, Equatorial Guinea.MethodsLLINs were analysed using the colorimetric Test Kit performed in situ, which leads to the formation of an orange-red solution whose depth of colour indicates the amount of type II pyrethroid on the net. The kit results were validated by measuring the amount of extracted insecticide using high-performance liquid chromatography (HPLC) with diode array detection (DAD).ResultsDeltamethrin concentration was determined for 130 LLINs by HPLC-DAD. The deltamethrin concentration of these nets exhibited a significant decrease with the age from 65 mg/m2 (<12 months of use) to 31 mg/m2 (>48 months; p<0.001). Overall, 18% of the nets being used in households had <15 mg/m2 of deltamethrin, thus falling into the failed category as assessed by the colorimetric Test Kit. This was supported by the bioassay determined bio-efficacy of the nets with ≥80% mortality following the World Health Organization (WHO) minimal effectiveness criteria. The Test Kit was field evaluated in situ and found to be rapid, accurate, and easy to use by people without laboratory training. The Test Kit was shown to have a reliable linear relationship between depth of colour produced and deltamethrin concentration (R2 = 0.9135).ConclusionResults of this study show that this colorimetric test was a reliable method to assess the insecticidal content of LLINs under operational conditions. The Test Kit provides immediate results and offers a rapid, inexpensive, field-friendly alternative to the complicated and costly methods as HPLC and WHO cone bioassays which also need specialist staff. Thus, enabling National Malaria Programs to gain access to effective and affordable monitoring tools for use in situ.

scholarly journals A colorimetric test for the evaluation of the insecticide content of LLINs used on Bioko Island, Equatorial Guinea

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Harparkash Kaur ◽  
Elizabeth Louise Allan ◽  
Teunis A. Eggelte ◽  
Guillermo A. García ◽  
Feliciano Monti
Keyword(s):  
Indoor Residual Spraying ◽  
Equatorial Guinea ◽  
Bed Nets ◽  
Type Ii ◽  
Insecticide Treated Nets ◽  
Operational Conditions ◽  
Bioko Island ◽  
Colorimetric Test ◽  
Test Kit

Abstract Background Insecticide-treated nets and indoor residual spraying of insecticides are used as the vector control interventions in the fight against malaria. Measuring the actual amount of deposits of insecticides on bed nets and walls is essential for evaluating the quality and effectiveness of the intervention. A colorimetric “Test Kit” designed for use as a screening tool, able to detect the type II pyrethroids on fabrics and sprayed walls, was used for the first time to detect deltamethrin on long-lasting insecticidal nets (LLINs) deployed on Bioko Island, Equatorial Guinea. Methods LLINs were analysed using the colorimetric Test Kit performed in situ, which leads to the formation of an orange-red solution whose depth of colour indicates the amount of type II pyrethroid on the net. The kit results were validated by measuring the amount of extracted insecticide using high-performance liquid chromatography (HPLC) with diode array detection (DAD). Results Deltamethrin concentration was determined for 130 LLINs by HPLC–DAD. The deltamethrin concentration of these nets exhibited a significant decrease with the age of the net from 65 mg/m2 (< 12 months of use) to 31 mg/m2 (> 48 months; p < 0.001). Overall, 18% of the nets being used in households had < 15 mg/m2 of deltamethrin, thus falling into the “Fail” category as assessed by the colorimetric Test Kit. This was supported by determining the bio-efficacy of the nets using the WHO recommended cone bioassays. The Test Kit was field evaluated in situ and found to be rapid, accurate, and easy to use by people without laboratory training. The Test Kit was shown to have a reliable linear relationship between the depth of colour produced and deltamethrin concentration (R2 = 0.9135). Conclusion This study shows that this colorimetric test was a reliable method to assess the insecticidal content of LLINs under operational conditions. The Test Kit provides immediate results and offers a rapid, inexpensive, field-friendly alternative to the complicated and costly methods such as HPLC and WHO cone bioassays which also need specialist staff. Thus, enabling National Malaria Control Programmes to gain access to effective and affordable monitoring tools for use in situ.

scholarly journals Malaria outbreak in Riaba district, Bioko Island, in 2019 – Lessons learnt

2020 ◽  
Author(s):  
Carlos A Guerra ◽  
Godwin Fuseini ◽  
Oliver Tresor Donfack ◽  
Jordan M Smith ◽  
Teresa Ayingono Ondo Mifumu ◽  
...  
Keyword(s):  
Vector Control ◽  
Malaria Incidence ◽  
Indoor Residual Spraying ◽  
Parasite Prevalence ◽  
National Guidelines ◽  
Breeding Sites ◽  
Bioko Island ◽  
Malaria Indicator Survey ◽  
Biting Rate

Abstract A sudden surge in malaria cases was observed in the district of Riaba, Bioko Island, at the start of 2019. Between January and April, confirmed malaria cases and malaria incidence increased about three-fold compared to the same period in 2018. Concurrently, anopheline human biting rate (HBR) increased 2.1-fold. During the outbreak, 82.2% of the district population was tested for malaria with a rapid diagnostic test and 37.2% were found positive and treated according to national guidelines. Vector control interventions, including indoor residual spraying and larval source management were scaled-up in response. After the interventions, the number of confirmed cases decreased by 70% and the overall parasite prevalence in the communities by 43.8%. Observed prevalence in a follow up malaria indicator survey, however, was significantly higher than elsewhere on the island and higher than in previous years. There was no significant reduction in HBR, which remained high for the rest of the year. The surge was attributed to various factors, chiefly increased rainfall and a large number of anthropogenic anopheline breeding sites created by construction works. This case study illustrates the need for sustained vector control interventions and multi-sector participation, particularly in malaria control settings with persistently high receptivity to local transmission.

scholarly journals Incidence of Plasmodium falciparum malaria infection in 6-month to 45-year-olds on selected areas of Bioko Island, Equatorial Guinea

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Vicente Urbano Nsue Ndong Nchama ◽  
Ali Hamad Said ◽  
Ali Mtoro ◽  
Gertrudis Owono Bidjimi ◽  
Marta Alene Owono ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Malaria Control ◽  
Malaria Infection ◽  
Age Groups ◽  
Control Measures ◽  
Equatorial Guinea ◽  
Safety And Efficacy ◽  
Bioko Island ◽  
Malaria Vaccines

Abstract Background Extensive malaria control measures have been implemented on Bioko Island, Equatorial Guinea over the past 16 years, reducing parasite prevalence and malaria-related morbidity and mortality, but without achieving elimination. Malaria vaccines offer hope for reducing the burden to zero. Three phase 1/2 studies have been conducted successfully on Bioko Island to evaluate the safety and efficacy of whole Plasmodium falciparum (Pf) sporozoite (SPZ) malaria vaccines. A large, pivotal trial of the safety and efficacy of the radiation-attenuated Sanaria® PfSPZ Vaccine against P. falciparum is planned for 2022. This study assessed the incidence of malaria at the phase 3 study site and characterized the influence of socio-demographic factors on the burden of malaria to guide trial design. Methods A cohort of 240 randomly selected individuals aged 6 months to 45 years from selected areas of North Bioko Province, Bioko Island, was followed for 24 weeks after clearance of parasitaemia. Assessment of clinical presentation consistent with malaria and thick blood smears were performed every 2 weeks. Incidence of first and multiple malaria infections per person-time of follow-up was estimated, compared between age groups, and examined for associated socio-demographic risk factors. Results There were 58 malaria infection episodes observed during the follow up period, including 47 first and 11 repeat infections. The incidence of malaria was 0.25 [95% CI (0.19, 0.32)] and of first malaria was 0.23 [95% CI (0.17, 0.30)] per person per 24 weeks (0.22 in 6–59-month-olds, 0.26 in 5–17-year-olds, 0.20 in 18–45-year-olds). Incidence of first malaria with symptoms was 0.13 [95% CI (0.09, 0.19)] per person per 24 weeks (0.16 in 6–59-month-olds, 0.10 in 5–17-year-olds, 0.11 in 18–45-year-olds). Multivariate assessment showed that study area, gender, malaria positivity at screening, and household socioeconomic status independently predicted the observed incidence of malaria. Conclusion Despite intensive malaria control efforts on Bioko Island, local transmission remains and is spread evenly throughout age groups. These incidence rates indicate moderate malaria transmission which may be sufficient to support future larger trials of PfSPZ Vaccine. The long-term goal is to conduct mass vaccination programmes to halt transmission and eliminate P. falciparum malaria.

The family Lecithoceridae (Lepidoptera, Gelechioidea) from Bioko Island (Equatorial Guinea), with descriptions of five new species

Zootaxa ◽  
2021 ◽  
Vol 4995 (3) ◽  
pp. 581-593
Author(s):  
KYU-TEK PARK ◽  
TIMM KARISCH
Keyword(s):  
New Species ◽  
Equatorial Guinea ◽  
Bioko Island ◽  
The Family ◽  
First Time ◽  
A New Species

Five new species belonging to the subfamily Torodorinae of Lecithoceridae are described from Bioko Island (Equatorial Guinea), based on specimens which were collected during a short expedition on the island by the second author in 1994. The new species are three species of the genus Thubdora Park, 2018 (T. biocoica sp. nov., T. vernaculella sp. nov., and T. angustiala sp. nov.), and a new species of Ptilothyris Walsingham, 1891and Dragmatucha Meyrick, 1908 respectively (Ptylothyris ruicheensis sp. nov.; and Dragmatucha vulcaniella sp. nov.). In addition, Thubdora bilobella Park, 2018 is reported for the first time from Equatorial Guinea. Images for adults and the genitalia of all species are given.  

scholarly journals Persistent Parasitemia Despite Dramatic Reduction in Malaria Incidence After 3 Rounds of Indoor Residual Spraying in Tororo, Uganda

2018 ◽  
Vol 219 (7) ◽  
pp. 1104-1111 ◽  
Author(s):  
Joaniter I Nankabirwa ◽  
Jessica Briggs ◽  
John Rek ◽  
Emmanuel Arinaitwe ◽  
Patience Nayebare ◽  
...  
Keyword(s):  
Malaria Incidence ◽  
Indoor Residual Spraying ◽  
Dramatic Reduction

scholarly journals The Effects of Nest Location and Beach Environment on Hatching Success for Leatherback (Dermochelys Coriacea) and Green (Chelonia Mydas) Sea Turtles on Bioko Island, Equatorial Guinea

2021 ◽  
Author(s):  
Callie A. Veelenturf ◽  
Elizabeth M. Sinclair ◽  
Peter Leopold ◽  
Frank V. Paladino ◽  
Shaya Honarvar
Keyword(s):  
Green Turtle ◽  
Hatching Success ◽  
Sea Turtles ◽  
Chelonia Mydas ◽  
Dermochelys Coriacea ◽  
Equatorial Guinea ◽  
Leatherback Turtles ◽  
Nest Location ◽  
Bioko Island ◽  
Elevation Range

Abstract Hatching success in sea turtles is hindered by a variety of biotic and abiotic factors. This study of the nesting ecology of leatherback (Dermochelys coriacea) and green (Chelonia mydas) sea turtles, investigated how several environmental factors and beach characteristics on Bioko Island, Equatorial Guinea influence sea turtle reproductive success. Average clutch hatching success was 40.4% for green turtles and 41.73% for leatherback turtles. For leatherback turtles, clutch elevation relative to the high tide line (HTL) was found to be the most influential factor in determining hatching success, highlighting the sensitivity of this species to sea level rise (SLR). Multiple linear regression analysis demonstrated that nest distance to vegetation and sand conductivity also played significant roles in leatherback clutch hatching success. For leatherback clutches, 33% percent of experimental nests were affected by inundation and 17% by predation. An optimum clutch elevation range for leatherback turtles was identified, where a distinct increase in hatching success was observed between -0.286 m to -0.0528 m above the HTL. For green sea turtles, 64% of experimental nests were affected by predation, confounding conclusions about the roles of environmental characteristics in green turtle hatching success. We propose further investigation into influential characteristics in green turtle nests and confirmation of the observed optimum elevation range on Bioko Island and other nesting grounds. Identified sensitivities of each species to SLR and beach characteristics will be used to encourage the government of Equatorial Guinea to consider the vulnerability of their resident turtle populations when planning for future coastal development.

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