DEPARTMENT OF ANIMAL AND ENVIRONMENTAL BIOLOGY

Food processing methods, particularly mechanical grinding, have been identified as potential sources of heavy metal contamination in daily diets. This study assessed the concentrations and health risks of heavy metals introduced into common Nigerian food items (tomato, pepper,melon, beans, groundnut, white and yellow corn, and crayfish) during grinding with various equipment types including blenders, milling machines, hand-crank grinders, mortars, and grinding stones. Heavy metals (Fe, Mn, Zn, Ni, Cd, and Pb) were analyzed using Atomic Absorption Spectrophotometry (AAS), and potential health risks were evaluated using Estimated Daily Intake (EDI) and Target Hazard Quotient (THQ) models. Results revealed elevated levels of essential metals such as Fe, Mn, and Zn, with concentrations highest in foods ground with older milling machines and mechanical grinders, reflecting increased leaching due to metallic wear. Toxic metals (Pb and Cd) were mostly below detection limits, indicating minimal immediate toxicity but potential for chronic accumulation. Fe showed the highest EDI (up to 5.35 mg/kg/day in hand-crank grinder samples), while THQ values exceeded 1.0 in several processed beans samples, suggesting possible non-carcinogenic risk upon prolonged exposure.Traditional grinding methods (mortar and pestle) exhibited significantly lower contamination levels compared to mechanical ones. These findings highlight that metal leaching from food processing equipment constitutes a significant but often overlooked route of dietary exposure to heavy metals in Nigeria.

Bisphenol A (BPA), a pervasive endocrine-disrupting chemical, poses significant ecological risks to aquatic organisms due to its widespread environmental contamination. This study investigates the effects of sublethal BPA concentrations on total protein levels in Clarias gariepinus (African catfish), a bioindicator species, to evaluate its sublethal toxicity and physiological implications. Following the organization for economic cooperation and development (OECD) guidelines for sublethal testing, fish were exposed to four BPA concentrations (1.25, 2.50, 5.0, and 10.0 mg/L) alongside positive (0.0 mg/L BPA) and negative (1.25 mg/L DMSO) controls under static conditions for 28 days. Total protein levels were quantified spectrophotometrically using the Biuret method, with statistical analysis performed via one-way ANOVA and Dunnett’s test (p < 0.05). Results revealed a significant dose-dependent reduction in total protein at higher concentrations (5.0 and 10.0 mg/L) after 7 days compared to controls (p< 0.05). However, these differences diminished by day 28, suggesting potential adaptive mechanisms or compensatory responses. The transient decline in protein levels at higher doses aligns with BPA-induced oxidative stress, which may impair hepatic protein synthesis or accelerate proteolysis. These findings underscore the time- and dose-dependent nature of BPA toxicity, highlighting its capacity to disrupt protein metabolism in aquatic organisms. The study emphasizes the need for stricter regulatory measures to mitigate BPA discharge into aquatic ecosystems, thereby reducing its sublethal impacts on fish physiology and broader ecological health.

Acanthamoeba species are free-living protozoa commonly found in water sources and are recognized causes of Acanthamoeba keratitis, particularly among contact lens wearers. Reticulated bore-hole water is widely used in many communities, yet data on its contamination with Acanthamoeba and the effectiveness of multipurpose contact lens solutions against these organisms remain limited. This study investigated the prevalence and species distribution of Acanthamoeba in reticulated bore-hole water and evaluated the efficacy of selected multipurpose contact lens solutions in reducing Acanthamoeba counts. A total of 36 reticulated bore-hole water samples were collected and cultured for Acanthamoeba species using standard parasitological techniques. For Acanthamoeba detection, 500ml of water was passed through a 0.45µm cellulose nitrate membrane filter. Prepared non-nutrient agar plates were seeded with heat-killed Escherichia coli. Cultures were incubated at 32ºC for Amoebic growth and examined microscopically. Isolates were identified based on morphological characteristics of trophozoite and cyst stages. The effects of three multipurpose contact lens solutions—FreesolTM, RefreshTM, and FreshlookTM—on Acanthamoeba counts were assessed. Data were analyzed using one-way analysis of variance (ANOVA) followed by Duncan’s multiple range test, with statistical significance set at p < 0.05. Acanthamoeba species were detected in 32 (88.9%) of the water samples, yielding a total of 209 isolates and a mean intensity of 6.53 detections per positive sample. Ten species were identified, with Acanthamoeba royreba showing the highest prevalence (17.7%), followed by A. polyphaga (11.96%), A. lenticulata and A. mauritaniensis (11.0% each). All contact lens solutions significantly reduced Acanthamoeba counts compared with pre-treatment levels (p < 0.05). Freesol achieved the greatest reduction (98 ± 9.5), followed by Refresh (101 ± 12.5), while Freshlook showed the least reduction (170 ± 22.0). None of the solutions completely eliminated Acanthamoeba. This study showed that reticulated bore-hole water harbored a high prevalence of potentially pathogenic Acanthamoeba species. Although multipurpose contact lens solutions significantly reduce Acanthamoeba burden, complete elimination was not achieved, highlighting the organism’s resistance and the continued risk of exposure. Strict adherence to proper contact lens hygiene and avoidance of bore-hole water use are essential to reduce the risk of Acanthamoeba infection.

Melanoides tuberculata is a freshwater snail of medical importance and serves as an intermediate host for several parasitic trematodes that affect both humans and animals. The aim of this study was to investigate the prevalence of trematode infections in M. tuberculata snails from River Siluko in Ovia South-West Local Government Area, Edo State, Nigeria. A total of 83 snails were collected in two batches: 17 and 66 specimens in May and July, 2025, respectively. All snails were subjected to standard cercarial shedding techniques and examined for the presence of trematode larvae under a dissecting microscope. Thereafter they were crushed and also examined. None of the snails shed cercaria. However, trematode larval stages (redia and furcocercous cercariae) were recovered from two (2.41%) of the snails examined after crushing. Only the snails examined in May were infected while none was infected in July. This finding showed that M. tuberculata from River Siluko harbors trematode infections, although at a relatively low prevalence. This indicates the role of M. tuberculata as an intermediate host for trematodes infection. The finding provides insight into the potential health risk posed by the aquatic environment of River Siluko. This study contributes to the understanding of the epidemiology of snail-borne trematode infections in the region and offers valuable data that can support public health planning, especially in community like Siluko that relied on water from the river for domestic and recreational activities. There is therefore need for continuous monitoring of freshwater snails parasites infection in the area.

The study investigated the effects of 6PPD-quinone (6PPD-Q) on the swimming performance of Clarias gariepinus fingerlings over a 28-day exposure period. Fish were exposed to nominal concentrations of 0 µg/L 6PPD-Q (positive control), 200 µg/L DMSO (negative control), and 500, 1000, and 1500 µg/L 6PPD-Q. Swimming speed showed a clear concentration and time dependent reduction across all treatment groups compared to the positive control. The mean swimming speeds (m/s) for the respective treatments were 2.115 ± 1.252, 0.8950 ± 0.2758, 0.8050 ± 0.0778, 0.1100 ± 0.0212, and 0.0250 ± 0.0071 on day 7; 4.110 ± 1.725, 0.4750 ± 0.1061, 0.0600 ± 0.0212, 0.0600 ± 0.0212, and 0.0150 ± 0.0071 on day 14; 0.8950 ± 0.2758, 0.6050 ± 0.0778, 0.1350 ± 0.0212, 0.0550 ± 0.0071, and 0.0350 ± 0.0071 on day 21; and 0.5800 ± 0.1838, 0.2500 ± 0.1556, 0.1650 ± 0.0495, and 0.0400 ± 0.0212 on day 28. Statistically significant differences (p <0.05) were observed between all 6PPD-Q-exposed groups and the positive control, except for the 200 µg/L and negative control groups on days 7, 21, and 28 (p > 0.05). Percentage reductions in swimming speed relative to the positive control were 57.7%, 61.9%, 94.8%, and 98.8% on day 7 for the negative control and 500, 1000, and 1500 µg/L groups, respectively. By day 21, reductions reached 32.4%, 84.9%, 93.9%, and 96.1%, and further deepened to 56.9%, 71.6%, 86.2%, and 93.1% by day 28. The observed decline in swimming performance indicates that 6PPD-Q impairs locomotor ability in C. gariepinus in a dose and duration dependent manner, potentially compromising survival and ecological fitness in contaminated aquatic environments

Mosquitoes are common insect pests and are well known as major vectors responsible for transmitting important parasitic and arboviral diseases such as malaria, filariasis, dengue fever, chikungunya and Zika virus, which pose significant health risks to humans and animals. This study investigated the species composition, sex ratio and distribution of outdoor-resting mosquitoes on the Ugbowo Campus of the University of Benin, Nigeria. Adult mosquitoes were sampled using sweep nets across 14 selected outdoor sites between 3:00 p.m. and 6:00 p.m. from August to September 2025. Identification was carried out using standard morphological keys. A total of 244 adult mosquitoes were recorded, representing seven species: Aedes albopictus (67.6%), Aedes infirmatus (2.87%), Aedes cretinus (0.4%), Aedes vexans (2.87%), Culex quinquefasciatus (25.4%), Coquillettidia fraseri (0.4%) and Mansonia sp. (0.4%). Aedes albopictus was the most abundant (67.6%) and the most widely distributed, occurring in all sampled locations except the Junior Staff Quarters farmland. Aedes cretinus, Coquillettidia fraseri and Mansonia sp. were the least represented, each accounting for 0.4%. The sex ratio showed a higher proportion of females (63.9%) than males (36.1%). The Junior Staff Quarters farmland had the highest mosquito abundance (17.6%), followed by the Faculty of Agriculture (11.5%) and the Ekosodin back gate (11.0%), while Hall 6 recorded the lowest abundance (2.5%). Species diversity was highest at the Faculty of Engineering, Basic Medical Sciences, and Hall 6, whereas the Department of Health Services and the Junior Staff Quarters plantain farm showed the lowest diversity.

This study evaluates heavy metal contamination in soils and earthworms (Aporrectodea longa) across three distinct sites—a botanical garden, an automobile repair workshop, and an industrial zone—to assess site-specific pollution impacts. Soil and earthworm samples were analyzed for zinc (Zn), copper (Cu), manganese (Mn), cobalt (Co), lead (Pb), cadmium (Cd), nickel (Ni), and iron (Fe). Results revealed stark contrasts: the industrial zone exhibited the highest contamination, with Cd averaging 0.2700 mg/kg in soil (peaking at 0.5250 mg/kg) and 0.01500 mg/kg in earthworms, exceeding regulatory thresholds. The automobile workshop showed elevated Pb (0.02100 mg/kg in soil) linked to vehicular emissions, while the botanical garden had relatively lower metal levels (Zn: 1.370 mg/kg in soil), though earthworms still accumulated significant Fe (3.342 mg/kg) and Cd (0.01450 mg/kg). Earthworm bioaccumulation patterns mirrored soil contamination, with industrial earthworms retaining hazardous Pb (0.03150 mg/kg) and Cd, underscoring their role as bioindicators. The automobile workshop’s earthworms exhibited suppressed metal uptake (Zn: 0.3600 mg/kg vs. soil Zn: 1.661 mg/kg), suggesting behavioral avoidance or toxicity effects. Conversely, botanical garden earthworms demonstrated moderate bioaccumulation despite lower soil pollution, hinting at atmospheric deposition. These findings highlight the industrial zone as a critical hotspot, with Cd posing severe ecological and human health risks due to its carcinogenic potential. The study advocates for urgent remediation in industrial areas, stricter regulation of automotive waste, and expanded use of earthworms in pollution monitoring. By linking land use to metal bioavailability, this research provides actionable insights for urban planning and environmental policy.

A parasitological study was carried out between May and June 2025, to determine the helminth parasites of Agama agama at the Internally Displaced Persons (IDP) Camp located at Uhogua Community, Ovia North-East Local Government Area of Edo State. The lizards were killed by exposure to chloroform, dissected and examined for helminth parasites. A total of 30 lizards were sampled and they were all infected, giving an overall prevalence of 100% and a mean intensity of 24.3 parasites/infected host. The parasites recovered included two nematode species, one species of cestode and a trematode. The nematodes were Strongyluris brevicaudata
and Thelandros scleratus, which were recovered from the large intestine/rectum and a few in the small intestine. The cestode species was Oochoristica sp. recovered from the small intestine and Mesocoelium monodi represented the trematodes, also from the small intestine. The most prevalent parasite was Strongyluris brevicaudata (76.67%), followed by Oochoristica sp. (43.33%) and the least prevalent, Mesocoelium monodi (10.0%). All the parasites recorded infected both male and female lizards, except Mesocoelium monodi, which was only reported in male Agama lizards. The difference in prevalence value amongst the helminth parasites reported was statistically significant (p < 0.05). More samples need to be examined from Uhogua in order to have more materials for proper identification of the Oochoristica sp., as well as to study other parasites that may be present in the study area but were not encountered due to the short duration of this study

A parasitological study was carried out between May and June 2025, to determine the helminth
parasites of Agama agama at the Internally Displaced Persons (IDP) Camp located at Uhogua
Community, Ovia North-East Local Government Area of Edo State. The lizards were killed by
exposure to chloroform, dissected and examined for helminth parasites. A total of 30 lizards
were sampled and they were all infected, giving an overall prevalence of 100% and a mean
intensity of 24.3 parasites/infected host. The parasites recovered included two nematode
species, one species of cestode and a trematode. The nematodes were Strongyluris brevicaudata
and Thelandros scleratus, which were recovered from the large intestine/rectum and a few in
the small intestine. The cestode species was Oochoristica sp. recovered from the small intestine
and Mesocoelium monodi represented the trematodes, also from the small intestine. The most
prevalent parasite was Strongyluris brevicaudata (76.67%), followed by Oochoristica sp.
(43.33%) and the least prevalent, Mesocoelium monodi (10.0%). All the parasites recorded
infected both male and female lizards, except Mesocoelium monodi, which was only reported
in male Agama lizards. The difference in prevalence value amongst the helminth parasites
reported was statistically significant (p < 0.05). More samples need to be examined from
Uhogua in order to have more materials for proper identification of the Oochoristica sp., as
well as to study other parasites that may be present in the study area but were not encountered
due to the short duration of this study

Amphibians play vital roles in our ecosystem as both predator and prey, contributing to insect population control and serving as a bio-indicator of the environmental health. This study was done to examine the food and feeding habits of anurans (Sclerophyrs maculata, Hoplobatrachus occipitalis, and Ptychadena pumilio) around the Faculty of Life Science towards the Department of Anatomy at the University of Benin, Edo state, Nigeria. A total of 62 specimen were captured and analyzed using the stomach-flushing method to obtain the stomach content and the prey items were identified. The result revealed that the anurans mainly consumed insects in the Order Hymenoptera, which was the most abundant and frequently occurring prey item (73.43%). Sclerophyrs maculata had the highest dietary diversity, while H. occipitalis showed a preference for Araneae (spiders) and Ptychadena pumilio showed the lowest prey diversity probably due to the number of specimens captured. This study provides insight into the adaptability of these species to their environment, demonstrating their opportunistic feeding habits and the factors influencing their diet. The high consumption of hymenoptera suggests that crawling insects are a readily available and preferred type of food. The presence of empty stomach might indicate low availability of food or fast digestion rate.