Efficient agri-food waste valorization using mealworm (Coleoptera: Tenebrionidae) into nutrient-rich biomass for food and feed.

The utilization of yellow mealworm, Tenebrio molitor (Linnaeus, Coleoptera: Tenebrionidae), for food and feed is gaining interest globally. However, its production is hindered by expensive commercial diets. This study assessed mealworm growth performance, survival, bioconversion, and nutritional composition when fed on wheat bran (WB) with different inclusion levels (25%, 50%, 75%, and 100%) of Irish potato waste (PW). Results indicated that mealworms fed on diets with 25%-75% PW had increased body length and 1-2 times higher weight gain compared to sole WB and PW diets. The survival rate was 93%-94% across all diets. Mealworms fed on WB had a feed conversion ratio of 3.26, while the efficiency of diet conversion increased with PW inclusion levels. Mealworms fed on diets with 75% PW inclusion had the highest crude fat (48%) and energy levels (598 kcal/100 g), while sole WB produced mealworms with the highest crude protein (55%). The acid detergent fiber achieved using 100% WB was 2- to 3-fold higher, but the crude fiber and neutral detergent fiber did not vary significantly. Considerable amounts of lysine (1.6-2 mg/100 g), methionine (0.5-0.7 mg/100 g), leucine (1.4-2 mg/100 g), and threonine (0.8-1 mg/100 g) were achieved in the mealworm larvae. Our findings revealed that cheap agricultural by-products could be successfully used for the mass production of mealworms, substantially contributing to reduced production costs. Further exploration of the nutrient-dense mealworm larvae for the development of novel food and feed products is crucial.

Assessment of the role played by domestic animals in jigger infection in Kandara sub-county, Kenya (case control study).

INTRODUCTION: tungiasis is an ectoparasitosis caused by penetration of female sand flea, Tunga penetrans, into the skin of the susceptible animal and the consequent hypertrophy of the parasite. The objective of this study was to assess the association between domestic animals and jigger infection among the residents of Kandara sub-county in central Kenya. METHODS: this was a case-control study that involved 776 individuals. Half of this number entailed case group who were jigger infected while the other half was the control, composed of jigger free participants. Structured questionnaires were, administered among the heads of the households to which the participants belonged to gather information concerning the animals they kept. Univariate analysis was, applied. RESULTS: in this study, there were significant differences in age (P=0.008) between the two groups. Disparities in source of income (P<0.001) and level of education (P<0.001) came out as very significant factors in jigger infection. The case group was 10 times more likely to keep dogs than the control(9.6; 95% CI, 5.9-15.6). Case group was also 7 times more likely to rear chicken in comparison to the control (6.6; 95%, 4.2-10.4). The case group was 12 times more likely to let dogs loose in the compound in comparison to the control (12.1: 95%, 5.9-24.5). When compared to the control, this group was also 17 times more likely to keep chicken inside their houses (16.7: 95% CI, 6.8-35.9). Conclusion: there is a very high association between domestic animals and occurrence of tungiasis in Kandara sub-county.

Larval species diversity, seasonal occurrence and larval habitat preference of mosquitoes transmitting Rift Valley fever and malaria in Baringo County, Kenya.

BACKGROUND: Baseline information that is essential for determining the areas to target with larval control includes estimates of vector diversity and larval habitat preferences. Due to a lack of such information in Baringo County, Kenya, this study assessed species diversity and larval habitat preference of potential mosquito vectors of Rift Valley fever (RVF) and malaria. METHODS: Mosquito larvae were sampled from nine types of larval habitats and were identified morphologically. Species diversity was estimated by the Shannon's diversity index while larval habitat preference by RVF and malaria vectors was determined by ANOVA. RESULTS: A total of 7724 immature mosquitoes comprising 17 species belonging to four genera, namely Anopheles, Culex, Aedes and Mansonia, were identified. Among the 17 species, three Anopheles species are responsible for malaria transmission: An. gambiae (s.l.), An. funestus (s.l.) and An. pharoensis. Rift Valley fever vectors included Mansonia spp. and Culex spp. The highest Shannon's diversity index was observed during the cold dry season (H = 2.487) and in the highland zone (H = 2.539) while the lowest diversity was recorded during the long rain season (H = 2.354) and in the riverine zone (H = 2.085). Ditches had the highest mean number of Anopheles larvae (16.6 larvae per sample) followed by swamp (12.4) and seasonal riverbed (10.7). Water pit and water pan had low mean numbers of Anopheles larvae (1.4 and 1.8, respectively) but relatively high mean numbers of culicines (16.9 and 13.7, respectively). Concrete tank was the least sampled type of habitat but had highest mean number of culicine larvae (333.7 l) followed distantly by water spring (38.9) and swamp (23.5). Overall, larval habitats were significantly different in terms of larval density (F(8,334) = 2.090, P = 0.036). CONCLUSIONS: To our knowledge, the present study reports culicine larval species diversity in Baringo for the first time and the most preferred habitats were concrete tanks, water springs and swamps. Habitats preferred by Anopheles were mainly riverbed pools, ditches and swamps. Environmental management targeting the habitats most preferred by potential vectors can be part of integrated vector control in Baringo, especially during dry seasons.

Spatial distribution, prevalence and potential risk factors of Tungiasis in Vihiga County, Kenya.

BACKGROUND: Tungiasis is a parasitic disease caused by the sand flea Tunga penetrans also known as jigger flea. Communities living in precarious conditions in tropical and sub tropical countries bear the brunt of the infection. The main objective of this study was to determine the burden of Tungiasis in Vihiga County in Kenya. METHODS: This was a cross-sectional study conducted in 21 villages in 3 Sub-locations in Vihiga County, western Kenya. A total of 437 participants, 5 years old and above were clinically examined for the presence of tungiasis after consenting to take part in the study. Diagnosis was made following standard methods. A semi- structured questionnaire was administered to assess socio-demographic factors, housing, presence and ownership of animals, knowledge and practice related to tungiasis. Data were analyzed using bivariate and multivariate regression analysis. GIS was used to map the geographic distribution of tungiasis in the area. RESULTS: The overall prevalence was found to be (21.5%; 95% CI: 17.7-25.3%). The cases were analysed and visualized in a map form. Multivariate analysis suggested that the occurrence of tungiasis was associated with variables that indicated low economic status (like a monthly income of Ksh ≤ 1000 (adjusted odds ratio 27.85; 95% CI: 4.13-187.59), earthen floor (0.36; 0.13-1.024) and lack of toilet facilities (4.27; 0.82-22.34), age of participant ≤14 (27.414; 10.02-74.99), no regular use of closed footwear (1.98; 0.987-3.97) and common resting place inside the house (1.93; 0.96-3.89). CONCLUSIONS: Tungiasis is an important health problem in Vihiga County occasioned by the low economic status of the people affected. Factors that point to poverty contribute to the occurrence of tungiasis. These findings suggest a need to design control strategies for tungiasis that are cost effective and easily accessible.

Malaria vector abundance is associated with house structures in Baringo County, Kenya.

Malaria, a major cause of morbidity and mortality, is the most prevalent vector borne disease in Baringo County; a region which has varied house designs in arid and semi-arid areas. This study investigated the association between house structures and indoor-malaria vector abundance in Baringo County. The density of malaria vectors in houses with open eaves was higher than that for houses with closed eaves. Grass thatched roof houses had higher density of malaria vectors than corrugated iron sheet roofs. Similarly, mud walled houses had higher vector density than other wall types. Houses in the riverine zone were significantly associated with malaria vector abundance (p<0.000) possibly due to more varied house structures. In Kamnarok village within riverine zone, a house made of grass thatched roof and mud wall but raised on stilts with domestic animals (sheep/goats) kept at the lower level had lower mosquito density (5.8 per collection) than ordinary houses made of same materials but at ground level (30.5 mosquitoes per collection), suggestive of a change in behavior of mosquito feeding and resting. House modifications such as screening of eaves, improvement of construction material and building stilted houses can be incorporated in the integrated vector management (IVM) strategy to complement insecticide treated bed nets and indoor residual spray to reduce indoor malaria vector density.

Status of insecticide resistance in malaria vectors in Kwale County, Coastal Kenya.

BACKGROUND: The strategy for malaria vector control in the context of reducing malaria morbidity and mortality has been the scale-up of long-lasting insecticidal nets to universal coverage and indoor residual spraying. This has led to significant decline in malaria transmission. However, these vector control strategies rely on insecticides which are threatened by insecticide resistance. In this study the status of pyrethroid resistance in malaria vectors and it's implication in malaria transmission at the Kenyan Coast was investigated. RESULTS: Using World Health Organization diagnostic bioassay, levels of phenotypic resistance to permethrin and deltamethrin was determined. Anopheles arabiensis showed high resistance to pyrethroids while Anopheles gambiae sensu stricto (s.s.) and Anopheles funestus showed low resistance and susceptibility, respectively. Anopheles gambiae sensu lato (s.l.) mosquitoes were further genotyped for L1014S and L1014F kdr mutation by real time PCR. An allele frequency of 1.33% for L1014S with no L1014F was detected. To evaluate the implication of pyrethroid resistance on malaria transmission, Plasmodium falciparum infection rates in field collected adult mosquitoes was determined using enzyme linked immunosorbent assay and further, the behaviour of the vectors was assessed by comparing indoor and outdoor proportions of mosquitoes collected. Sporozoite infection rate was observed at 4.94 and 2.60% in An. funestus s.l. and An. gambiae s.l., respectively. A higher density of malaria vectors was collected outdoor and this also corresponded with high Plasmodium infection rates outdoor. CONCLUSIONS: This study showed phenotypic resistance to pyrethroids and low frequency of L1014S kdr mutation in An. gambiae s.l. The occurrence of phenotypic resistance with low levels of kdr frequencies highlights the need to investigate other mechanisms of resistance. Despite being susceptible to pyrethroids An. funestus s.l. could be driving malaria infections in the area.

Secondary bacterial infections and antibiotic resistance among tungiasis patients in Western, Kenya.

Tungiasis or jigger infestation is a parasitic disease caused by the female sand flea Tunga penetrans. Secondary infection of the lesions caused by this flea is common in endemic communities. This study sought to shed light on the bacterial pathogens causing secondary infections in tungiasis lesions and their susceptibility profiles to commonly prescribed antibiotics. Participants were recruited with the help of Community Health Workers. Swabs were taken from lesions which showed signs of secondary infection. Identification of suspected bacteria colonies was done by colony morphology, Gram staining, and biochemical tests. The Kirby Bauer disc diffusion test was used to determine the drug susceptibility profiles. Out of 37 participants, from whom swabs were collected, specimen were positive in 29 and 8 had no growth. From these, 10 different strains of bacteria were isolated. Two were Gram positive bacteria and they were, Staphylococcus epidermidis (38.3%) and Staphylococcus aureus (21.3%). Eight were Gram negative namely Enterobacter cloacae (8.5%), Proteus species (8.5%), Klebsiellla species (6.4%), Aeromonas sobria (4.3%), Citrobacter species (4.3%), Proteus mirabillis(4.3%), Enterobacter amnigenus (2.1%) and Klebsiella pneumoniae (2.1%). The methicillin resistant S. aureus (MRSA) isolated were also resistant to clindamycin, kanamycin, erythromycin, nalidixic acid, trimethorprim sulfamethoxazole and tetracycline. All the Gram negative and Gram positive bacteria isolates were sensitive to gentamicin and norfloxacin drugs. Results from this study confirms the presence of resistant bacteria in tungiasis lesions hence highlighting the significance of secondary infection of the lesions in endemic communties. This therefore suggests that antimicrobial susceptibility testing may be considered to guide in identification of appropriate antibiotics and treatment therapy among tungiasis patients.

Development of a gravid trap for collecting live malaria vectors Anopheles gambiae s.l.

BACKGROUND: Effective malaria vector control targeting indoor host-seeking mosquitoes has resulted in fewer vectors entering houses in many areas of sub-Saharan Africa, with the proportion of vectors outdoors becoming more important in the transmission of this disease. This study aimed to develop a gravid trap for the outdoor collection of the malaria vector Anopheles gambiae s.l. based on evaluation and modification of commercially available gravid traps. METHODS: Experiments were implemented in an 80 m(2) semi-field system where 200 gravid Anopheles gambiae s.s. were released nightly. The efficacy of the Box, CDC and Frommer updraft gravid traps was compared. The Box gravid trap was tested to determine if the presence of the trap over water and the trap's sound affected catch size. Mosquitoes approaching the treatment were evaluated using electrocuting nets or detergents added to the water in the trap. Based on the results, a new gravid trap (OviART trap) that provided an open, unobstructed oviposition site was developed and evaluated. RESULTS: Box and CDC gravid traps collected similar numbers (relative rate (RR) 0.8, 95% confidence interval (CI) 0.6-1.2; p = 0.284), whereas the Frommer trap caught 70% fewer mosquitoes (RR 0.3, 95% CI 0.2-0.5; p < 0.001). The number of mosquitoes approaching the Box trap was significantly reduced when the trap was positioned over a water-filled basin compared to an open pond (RR 0.7 95% CI 0.6-0.7; p < 0.001). This effect was not due to the sound of the trap. Catch size increased by 60% (RR 1.6, 1.2-2.2; p = 0.001) with the new OviART trap. CONCLUSION: Gravid An. Gambiae s.s. females were visually deterred by the presence of the trapping device directly over the oviposition medium. Based on these investigations, an effective gravid trap was developed that provides open landing space for egg-laying Anopheles.

Electric nets and sticky materials for analysing oviposition behaviour of gravid malaria vectors.

BACKGROUND: Little is known about how malaria mosquitoes locate oviposition sites in nature. Such knowledge is important to help devise monitoring and control measures that could be used to target gravid females. This study set out to develop a suite of tools that can be used to study the attraction of gravid Anopheles gambiae s.s. towards visual or olfactory cues associated with aquatic habitats. METHODS: Firstly, the study developed and assessed methods for using electrocuting nets to analyse the orientation of gravid females towards an aquatic habitat. Electric nets (1m high × 0.5m wide) were powered by a 12V battery via a spark box. High and low energy settings were compared for mosquito electrocution and a collection device developed to retain electrocuted mosquitoes when falling to the ground. Secondly, a range of sticky materials and a detergent were tested to quantify if and where gravid females land to lay their eggs, by treating the edge of the ponds and the water surface. A randomized complete block design was used for all experiments with 200 mosquitoes released each day. Experiments were conducted in screened semi-field systems using insectary-reared An. gambiae s.s. Data were analysed by generalized estimating equations. RESULTS: An electric net operated at the highest spark box energy of a 400 volt direct current made the net spark, creating a crackling sound, a burst of light and a burning smell. This setting caught 64% less mosquitoes than a net powered by reduced voltage output that could neither be heard nor seen (odds ratio (OR) 0.46; 95% confidence interval (CI) 0.40-0.53, p < 0.001). Three sticky boards (transparent film, glue coated black fly-screen and yellow film) were evaluated as catching devices under electric nets and the transparent and shiny black surfaces were found highly attractive (OR 41.6, 95% CI 19.8 - 87.3, p < 0.001 and OR 28.8, 95% CI 14.5 - 56.8, p < 0.001, respectively) for gravid mosquitoes to land on compared to a yellow sticky film board and therefore unsuitable as collection device under the e-nets. With a square of four e-nets around a pond combined with yellow sticky boards on average 33% (95% CI 28-38%) of mosquitoes released were collected. Sticky materials and detergent in the water worked well in collecting mosquitoes when landing on the edge of the pond or on the water surface. Over 80% of collected females were found on the water surface (mean 103, 95% CI 93-115) as compared to the edge of the artificial pond (mean 24, 95% CI 20-28). CONCLUSION: A square of four e-nets with yellow sticky boards as a collection device can be used for quantifying the numbers of mosquitoes approaching a small oviposition site. Shiny sticky surfaces attract gravid females possibly because they are visually mistaken as aquatic habitats. These materials might be developed further as gravid traps. Anopheles gambiae s.s. primarily land on the water surface for oviposition. This behaviour can be exploited for the development of new trapping and control strategies.

Seasonal changes of infectivity rates of Bancroftian filariasis vectors in coast province, Kenya.

BACKGROUND & OBJECTIVES: Bancroftian filariasis in Kenya is endemic in coastal districts with an estimated number of 2.5 million people at risk of infection. The main mosquito genera involved in transmission of Wuchereria bancrofti in these areas are Anopheles, Culex and Mansonia. The study was envisaged to compare the infectivity rates of Bancroftian filariasis vectors between the high transmission (wet) and the low transmission (dry) seasons. METHODS: Mosquitoes were sampled from houses and compounds from two study sites, Gazi and Madunguni, on the Kenyan coast. Day resting indoor collection (DRI), pyrethrum spray catch (PSC) and CDC light traps were used to collect mosquitoes. After identification, female mosquitoes were dissected to search for W. bancrofti III stage larvae. RESULTS: A total of 1832 female mosquitoes were dissected. Infectivity rates of vectors in Madunguni were 1.49 and 0.21% in wet and dry seasons respectively, whereas in Gazi, these were 1.69 and 0%, respectively. There was a significant difference in the infectivity rates between the two seasons in both Madunguni and Gazi villages (p <0.05). Anopheles gambiae s.l. was the main vector in both study sites followed by Culex quinquefasciatus and An. funestus. CONCLUSION: There was a difference in infectivity rates of Bancroftian filariasis vectors between the wet and dry seasons. The abundance of An. gambiae s.s. during the transmission season could be responsible for the increased infectivity rates of vectors in this season.