Elick Otachi
University of Vienna, Evolutionary Biology, Graduate Student
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The present study was conducted to assess the levels of selected organochlorine pesticide (OCP) residues in water, sediments and Nile tilapia, as well as the potential health risks to humans who consume the fish of Lake Nakuru. Nine... more
The present study was conducted to assess the levels of selected organochlorine pesticide (OCP) residues in water, sediments and Nile tilapia, as well as the potential health risks to humans who consume the fish of Lake Nakuru. Nine composite water and nine sediment samples, as well as 30 fish specimens, were collected from five representative sampling sites within Lake Nakuru. The OCPs targeted in the present study included p,p′‐Dichlorodiphenyl dichloroethane (p,p′‐DDD), p,p′‐dichlorodiphenyldichloroethylene (p,p′‐DDE), p,p′‐dichlorodiphenyltrichloroethane (p,p′‐DDT), heptachlor, heptachlor epoxide, α endosulfan (1), β endosulfan (2), endosulfan sulphate, endrin, lindane, aldrin, dieldrin, methoxychlor and hexachlorocyclohexanes (alpha; beta; gamma; delta). Except for aldrin, all 16 OCPs targeted in the present study were detected. The OCP residue levels ranged from below detection limit (BDL) to 7.44 ± 0.66 μg/L, BDL to 6.39 ± 1.10 μg/kg ww and BDL to 319.74 ± 66.94 μg/kg ww in water, sediment and fish samples respectively. Some OCP concentrations exhibited significant differences across the sampling sites (p < .05). The residue level of endosulfan was above the European Union standard, whereas the target hazard quotient of heptachlor epoxide was above 1, therefore being unsafe for human consumption. The present study results indicate that most of organochlorine pesticides though banned in Kenya are still detected in the environment, posing potential long‐term health hazards to humans. Accordingly, environmental monitoring programme and mitigation strategies of reducing pollutant inputs into the lake is recommended, as well as an immediate ban on harvesting and consumption of fish from Lake Nakuru.
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Research Interests: Environmental Science, Ecotoxicology, Environmental Monitoring, Environmental Chemistry, Risk assessment, and 15 moreKenya, Water Pollution, Medicine, Lakes, Heavy metals, Environmental Sciences, Humans, Animals, Pollution, Sediment, Trace Elements, Characiformes, CHEMICAL SCIENCES, Risk Assessment, and Hazard quotient
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Even in the relatively well-characterized faunas of the developed world, it is difficult to discriminate species of metacercariae in the Diplostomidae using morphology, infection site or host use. The taxonomy, diversity and ecology of... more
Even in the relatively well-characterized faunas of the developed world, it is difficult to discriminate species of metacercariae in the Diplostomidae using morphology, infection site or host use. The taxonomy, diversity and ecology of diplostomids infecting freshwater fishes in the African continent are particularly poorly known, but recent morphometric and genetic studies have revealed four species of diplostomids in the eyes and brains of siluriform fishes. In the present study, diplostomid metacercariae were collected from the eyes of 288 fish comprising two species within the Cyprinidae (Cyprinus carpio, n= 145, and Barbus paludinosus, n= 67), two Cichlidae (Oreochromis leucostictus, n= 56, and Tilapia zillii, n= 18) and one Centrarchidae (Micropterus salmoides, n= 2) caught in Lake Naivasha, Kenya. Morphometric (14 characters and 8 indices in 111 specimens) and molecular (sequences from the barcode region of the cytochrome c oxidase 1 gene in 11 specimens) data were used to discriminate species. All fish species except B. paludinosus were infected with Tylodelphys metacercariae that were initially separated into two types differing mainly in body length. However, this morphological distinction received only intermediate support in quantitative morphological analysis and molecular data indicated that both morphotypes were conspecific. All the specimens therefore are inferred to belong to a single unidentified species of Tylodelphys, which is not conspecific with any other diplostomid for which comparable molecular data are available, including four diplostomid species known from siluriform fish in Nigeria and Tanzania.
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There have been several studies on heavy metals in Lake Naivasha. However, none of them has reported the levels of mercury (Hg), arsenic (As), and chromium (Cr). Moreover, there are no studies on the heavy metals’ concentrations in the... more
There have been several studies on heavy metals in Lake Naivasha. However, none of them has reported the levels of mercury (Hg), arsenic (As), and chromium (Cr). Moreover, there are no studies on the heavy metals’ concentrations in the straightfin barb (Enteromius paludinosus, Peters 1852), a fish species that hosts a parasite (Ligula intestinalis), the latter having been reported to have a high ability to absorb heavy metals from its host. This paper therefore addresses the accumulation of heavy metals, namely arsenic (As), chromium (Cr), lead (Pb), and mercury (Hg) in the tissues of straightfin barb, Enteromius paludinosus (Peters 1852) from the mouth of River Malewa in Lake Naivasha, Kenya. A total of 1307 fish were collected during the month of November 2017. Water samples, sediment samples, 25 fish muscle tissues, and its endoparasite, the cestode Ligula intestinalis, were isolated, and heavy metal concentrations were determined using the thermal-electron atomic absorption spectrophotometer at the Lake Nakuru Water Quality Testing Laboratory. The concentrations of heavy metals in the sediment were below the lowest effect level in sediment, threshold effect concentration in sediment, severe effect concentration in sediment, and the shale values of sedimentary rocks thus showing no sign of pollution. In the muscle tissues of the fish, As, Cr, Pb, and Hg showed high levels with mean concentrations of 5.0696, 22.0854, 45.2108, and 1.5458 mg/kg ww, respectively. Bioconcentration factors further supported the observation that trace element accumulation was higher in fish compared with sediment and water. The target hazard quotients of As, Cr, Pb, and Hg obtained for both the female and male were > 1 indicating a possible health risk associated with the consumption of E. paludinosus. The bioaccumulation factors (BAFs) for L. intestinalis were 2.4093, 2.1873, 5.8601, and 5.1395 for As, Cr, Pb, and Hg, respectively, indicating the potential of the cestode in the accumulation of heavy metals from the host; hence, it can be used as an accumulation bioindicator.
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In Kenya, breeding programmes whose source of genetic material is local water bodies are at inception with the National Aquaculture Research Center, Sagana being the Nile tilapia and African catfish breeding nucleus. Fish are susceptible... more
In Kenya, breeding programmes whose source of genetic material is local water bodies are at inception with the National Aquaculture Research Center, Sagana being the Nile tilapia and African catfish breeding nucleus. Fish are susceptible to a variety of infections and diseases. These microorganisms are often present on the external surfaces and visceral organs of the fish. In order to minimize fish disease burdens a number of fish health management practices and biosecurity measures have been recommended. In this study, a combination of new genetically improved fish strains, liming, netting and biofloc technologies were used in selected fish farms in Busia and Siaya Counties for validation. A total of 113 Nile tilapia were collected (93 from Bukani Aquaparks and 20 from WOODM fish farm) using a seine net. The fish were killed by cervical dislocation. This was followed with measurements of the total lengths and weights. Standard examination procedures were used. A total of 6 differen...
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Fasciolosis is caused by digenean trematodes of the genus Fasciola. The principal definitive hosts are cattle, sheep and goats. Humans are infected as accidental hosts. Fasciolosis is one of the major neglected tropical diseases and is... more
Fasciolosis is caused by digenean trematodes of the genus Fasciola. The principal definitive hosts are cattle, sheep and goats. Humans are infected as accidental hosts. Fasciolosis is one of the major neglected tropical diseases and is considered an emerging zoonotic infection. This study was aimed at determining the prevalence of human and domestic animal fasciolosis in selected counties in Kenya. Stool samples for Fasciola diagnosis were collected from humans and domestic animals and transported to the laboratory at Egerton University and processed using sedimentation technique and examined for the presence of eggs. A total of 272 human samples collected were all negative for Fasciola eggs. A total of 582 domestic animals (cattle (46.0%), sheep (29.9%) and goats (24.1%)) samples collected had overall prevalence of 30.9% for Fasciola infection. There was no significant differences (p0.05) between prevalence of fasciolosis and origin of the animals, sex and season. There was a signi...
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Use of microalgae as source of food in aquaculture production is gaining recognition due to their rapid growth rate that promises high biomass generation within a short time. The challenge faced is getting good and inexpensive nutrients... more
Use of microalgae as source of food in aquaculture production is gaining recognition due to their rapid growth rate that promises high biomass generation within a short time. The challenge faced is getting good and inexpensive nutrients source to be used in mass production of the required microalgae. This study investigated the effect of different nutrient combination in influencing the growth rate of the of the green algae Oocystis sp. which has been indentified as possible protein source for the raising of Orechromis niloticus fingerlings for fish farming. Modified Bolds 3N Medium and commercial agricultural fertilisers (urea, NPK and DAP) media were compared to establish the appropriate combination that would result into high biomass generation but at the lowest cost possible. The Modified Bold 3N Medium acted as the control, at a cost of 11.28 KSh per litre, the other media were derived from urea, NPK and DAP (varying the ratio of each) at a cost of treatment 1 (0.14 KSh per lit...
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Aquaculture is one of the critical sectors contributing to food and nutrition security, income and employment opportunities to millions of people and is currently the fastest growing food-producing sector globally. With the global... more
Aquaculture is one of the critical sectors contributing to food and nutrition security, income and employment opportunities to millions of people and is currently the fastest growing food-producing sector globally. With the global increase in aquaculture production, focus on biosecurity and fish health management is becoming increasingly important to address the risks and impacts of aquatic diseases. Within the framework of adaptive research, this study aimed at assessing the levels of awareness and preparedness of fish farmers in Western Kenya to meet fish health management and biosecurity requirements as important parameters determining the success of their farming activities. A total of 243 fish farmers were interviewed using a pre-tested questionnaire generated by a computer-aided personal interview (CAPI). The key findings were that 76.1% of the fish farmers reported mortalities in their farms, with 2.3% reporting mortalities above 50% of the stocked fish, but with a majority 8...
1 Dept. Veterinary Public Health and Animal Pathology, Bologna University, Italy; 2 Dept. Public Health, Comparative Pathology & Veterinary Hygiene, University of Padua, Italy; 3 Environment Agency, Vienna, Austria; 4 Dept. Freshwater... more
1 Dept. Veterinary Public Health and Animal Pathology, Bologna University, Italy; 2 Dept. Public Health, Comparative Pathology & Veterinary Hygiene, University of Padua, Italy; 3 Environment Agency, Vienna, Austria; 4 Dept. Freshwater Ecology, University of Vienna, Austria ; 5 Egerton University, Kenya; 6 Moi University, Kenya; 7 Sagana Fish Culture Farm, Kenyan Ministry of Fisheries Development, Kenya; 8 Kenya Marine & Fisheries Research Institute, Kenya ; Dept. Zoology, Makerere University, Kampala, Uganda; 10 Dept. of Aquaculture, Ministry of Agriculture, Animal Industry and Fisheries, Entebbe, Uganda; 11 Ethiopian Institute of Aquaculture Research, Addis Ababa, Ethiopia. _______________________________
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Cryptosporidium spp. cause Cryptosporidiosis in humans through zoonotic and anthroponotic transmission. Previous studies have illustrated the significance of domestic animals as reservoirs of this parasite. However, there is no... more
Cryptosporidium spp. cause Cryptosporidiosis in humans through zoonotic and anthroponotic transmission. Previous studies have illustrated the significance of domestic animals as reservoirs of this parasite. However, there is no information on the Cryptosporidium spp. and genotypes circulating in Njoro Sub County. A total of 2174 samples from humans, cattle, chicken, sheep and goats were assessed for presence of Cryptosporidium spp. Thirty-three positive samples were successfully sequenced. The sequences obtained were compared to Cryptosporidium sequences in the GenBank using NCBI’s (National Center for Biotechnology Information) online BLAST (Basic Local Alignment Search Tool) algorithmic program. Sequence alignment was done using the Clustal W program and phylogenetic analysis was executed in MEGA 6 (Molecular Evolutionary Genetics Analysis version 6.0). The Cryptosporidium spp. present in the watershed showed great genetic diversity with nine (9) Cryptosporidium spp. namely: C. pa...
Lake Turkana fishery consists of seven endemic and 12 commercially exploited species and is the second largest producer of freshwater fish in Kenya. It supports livelihoods of approx. 300,000 people locally. The lake is managed by beach... more
Lake Turkana fishery consists of seven endemic and 12 commercially exploited species and is the second largest producer of freshwater fish in Kenya. It supports livelihoods of approx. 300,000 people locally. The lake is managed by beach management units (BMU) through a co-management arrangement between the government and stakeholders. Despite this, it faces management related challenges that have resulted in plummeting fish production due to uncontrolled fishing effort, increased competition among fishermen and deficient statistics to support management objectives. This study investigated institutional factors influencing BMUs’ performance by examining training and level of understanding of BMU laws and regulations, funding sources and usage and equipment ownership. A cross-sectional study was adopted and purposive sampling used to collect data from 693 respondents using questionnaires. Chi square was used to test for statistical differences at 95% significant level using MINITAB st...
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Aquaculture is an important source of food globally. The Kenya Government through the economic stimulus package (ESP) in a supplementary budget of 2009/2010, allocated Kshs.1.12 Billion for the establishment of 200 fish ponds in each of... more
Aquaculture is an important source of food globally. The Kenya Government through the economic stimulus package (ESP) in a supplementary budget of 2009/2010, allocated Kshs.1.12 Billion for the establishment of 200 fish ponds in each of the 140 potential constituencies in an effort aimed at enhancing food security by increasing fish production in the country. Fish diseases and parasitic infections have been and still remain peripherally recognized as one of the detrimental and limiting factors in the development of the aquaculture sector. This research was set to study the diffusion and dispersion of parasites in Oreochromis niloticus fish cultured in a typical hub and plot system in an integrated cage fish culture in Kenya. The system was based on a hub (source of seed) from Sagana Aquaculture Centre and a plot (farm) in Machakos, KwaNgeki reservoir. Specific objectives were to detect and identify parasites, determine their prevalence, mean intensity and abundance; and compare the ...
Cryptosporidium spp. cause cryptosporidiosis in humans through zoonotic and anthroponotic transmission. Previous studies illustrated the significance of domestic animals as reservoirs of this parasite. Cryptosporidium occurs in Njoro... more
Cryptosporidium spp. cause cryptosporidiosis in humans through zoonotic and anthroponotic transmission. Previous studies illustrated the significance of domestic animals as reservoirs of this parasite. Cryptosporidium occurs in Njoro River; a main source of water to humans and animals. However, there is no information on the Cryptosporidium spp. and genotypes circulating in Njoro Sub County. A total of 2174 samples from humans, cattle, chickens, sheep and goats were assessed for the presence of Cryptosporidium spp. Thirty-three positive samples were subsequently successfully sequenced and compared to Cryptosporidium sequences in the GenBank repository using NCBI’s (National Center for Biotechnology Information) online BLAST (Basic Local Alignment Search Tool) algorithmic program. Sequence alignment was done using the Clustal W program and phylogenetic analysis was executed in MEGA X (Molecular Evolutionary Genetics Analysis version X). The prevalence of cryptosporidiosis in Njoro Su...
Water quality has been documented to affect the biology and well-being of fish. This study therefore investigated some aspects of Oreochromis niloticus baringoensis (Trewavas, 1983) fishery assessment and the influence of selected water... more
Water quality has been documented to affect the biology and well-being of fish. This study therefore investigated some aspects of Oreochromis niloticus baringoensis (Trewavas, 1983) fishery assessment and the influence of selected water quality parameters in two hot springs draining into Lorwai Sw& Lake Bogoria Spa spring and Chelaba spring between the months of July and August, 2018. A total of 445 fish were collected; 244 from Lake Bogoria Spa spring and 201 from Chelaba spring using a seine net. Length Weight Relationship (LWR) was determined using Le Cren’s equation; W=aTLb and Fulton’s condition factor (k) determined using Ricker’s equation; 100W/L3. LWR results indicated an isometric growth for fish from both springs. The mean (± SD) k values for fish in Lake Bogoria Spa spring were 2.02±0.25 for the males, 2.02±0.27 for the females and 2.00±0.26 for both sexes. In Chelaba spring, the mean k values were 2.03±0.21 for the males, 1.97±0.25 for the females and 2.00±0.23 for both ...
Fische stellen sowohl fur die Bevolkerung der Regionen um den Naivasha- und den Turkanasee als auch fur die Gesamtbevolkerung Kenias eine wichtige Proteinquelle dar. Im Gegensatz zum Naivashasee, wo der Fischbestand aus Besatz stammt, ist... more
Fische stellen sowohl fur die Bevolkerung der Regionen um den Naivasha- und den Turkanasee als auch fur die Gesamtbevolkerung Kenias eine wichtige Proteinquelle dar. Im Gegensatz zum Naivashasee, wo der Fischbestand aus Besatz stammt, ist der Fischbestand im Turkanasee autochthon. Die Ziele dieser Studie waren einerseits das Vorkommen von Parasiten in kommerziell bedeutsamen Fischen aus den beiden Seen zu untersuchen und andererseits die Analyse von Spurenelementen in mehreren Kompartimenten (Wasser, Sediment, Fischorgane und Fischparasiten) um eventuelle Gesundheitsrisiken fur Konsumenten von Fischen aus den beiden Seen festzustellen. Auserdem wurde das Potential einiger Fischparasiten als Bioindikator untersucht. Insgesamt wurden 373 Fische zur Untersuchung herangezogen und zwar 145 Karpfen Cyprinus carpio, 56 Weissfleckenmaulbruter Oreochromis leucostictus, 18 Zilles Buntbarsche Tilapia zillii und 67 Sumpfbarben Barbus paludinosus aus dem Naivashasee sowie 43 Exemplare von Hydroc...
Fasciolosis is a neglected trematode infection of public health and veterinary importance caused by Fasciola gigantica and Fasciola hepatica. Molecular analysis using the internal transcribed spacers’ ITS-1 and ITS-2 of nuclear ribosomal... more
Fasciolosis is a neglected trematode infection of public health and veterinary importance caused by Fasciola gigantica and Fasciola hepatica. Molecular analysis using the internal transcribed spacers’ ITS-1 and ITS-2 of nuclear ribosomal DNA is useful in distinguishing Fasciola species. This study aimed to characterize liver flukes from sheep, goats and cattle using these genetic markers. Fifty nine adult Fasciola specimens were collected from livers of naturally infected sheep, goats and cattle at selected abattoirs in Kisumu, Baringo and Narok Counties. Sequence comparison of ITS-1 and ITS-2 sequences of Fasciola isolates from this study and sequences in Genbank was carried out. A maximum likelihood tree was constructed for phylogenetic analysis. Analysis of ITS-1 and ITS-2 rDNA sequences revealed that F. hepatica and F. gigantica caused infection in both cattle and sheep and in goats only F. gigantica caused infection. The sequenced PCR amplicons showed a close relationship betwe...
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Fish are a resource with great economic, nutritional and recreational benefits to humans on a global scale. In Kenya, fish represent an important source of food and income through trade and employment to many communities. In fact, fish... more
Fish are a resource with great economic, nutritional and recreational benefits to humans on a global scale. In Kenya, fish represent an important source of food and income through trade and employment to many communities. In fact, fish are an important alternative source of animal protein, especially in famine-tolerant arid and semi-arid regions such as Turkana, Marsabit, Pokot and Baringo Counties, where annual drought periodically hampers traditional livestock keeping destitute. Kenya freshwater fishes have remained vulnerable to a variety of parasites and related diseases. Approximately 119 fish parasites have been reported in the country, with about 83 being identified to species level and 35 to genus level. Out of the reported parasites, 77% were detected in wild fish, 8% in farm fish and 15% in both wild and farmed fish. The parasites identified by various studies include protozoa (7), myxozoa (7), nematode (20), monogenean (33), digenean (16), cestoda (15), acanthocephalan (6) and crustacean (15). The highly commercialized fishes, such as Oreochromis niloti-cus and Clarias gariepinus, harbour the highest number of parasites, which greatly hinder fisheries and aquaculture productivity through retarded growth, mechanical damages, reduced reproduction rates and increased mortality of the fish hosts. Thus, there is need for adequate information on the taxonomy and ecology of these parasites as a basis for developing appropriate management and policies to control them. This review article is meant to provide an overview of the distribution, occurrence of fish parasites and their impacts on inland water fisheries and aquaculture in Kenya, while also highlighting the available gaps warranting further studies, with the goal of developing appropriate and accurate control measures to improve the region's fisheries and aquaculture productivity and food security. K E Y W O R D S freshwater systems, impacts, Kenyan inland water, parasites, taxonomy
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Even in the relatively well-characterized faunas of the developed world, it is difficult to discriminate species of metacercariae in the Diplostomidae using morphology, infection site or host use. The taxonomy, diversity and ecology of... more
Even in the relatively well-characterized faunas of the developed world, it is difficult to discriminate species of metacercariae in the Diplostomidae using morphology, infection site or host use. The taxonomy, diversity and ecology of diplostomids infecting freshwater fishes in the African continent are particularly poorly known, but recent morphometric and genetic studies have revealed four species of diplostomids in the eyes and brains of siluriform fishes. In the present study, diplostomid metacercariae were collected from the eyes of 288 fish comprising two species within the Cyprinidae (Cyprinus carpio, n= 145, and Barbus paludinosus, n= 67), two Cichlidae (Oreochromis leucostictus, n= 56, and Tilapia zillii, n= 18) and one Centrarchidae (Micropterus salmoides, n= 2) caught in Lake Naivasha, Kenya. Morphometric (14 characters and 8 indices in 111 specimens) and molecular (sequences from the barcode region of the cytochrome c oxidase 1 gene in 11 specimens) data were used to discriminate species. All fish species except B. paludinosus were infected with Tylodelphys metacercariae that were initially separated into two types differing mainly in body length. However, this morphological distinction received only intermediate support in quantitative morphological analysis and molecular data indicated that both morphotypes were conspecific. All the specimens therefore are inferred to belong to a single unidentified species of Tylodelphys, which is not conspecific with any other diplostomid for which comparable molecular data are available, including four diplostomid species known from siluriform fish in Nigeria and Tanzania.
Research Interests: Zoology and Helminthology
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The combined use of morphological and molecular studies allowed for the first time the recognition and description of the adult stage of Clinostomum cutaneum Paperna, 1964 from the grey heron Ardea cinerea L. in Kenya. A redescription of... more
The combined use of morphological and molecular studies allowed for the first time the recognition and description of the adult stage of Clinostomum cutaneum Paperna, 1964 from the grey heron Ardea cinerea L. in Kenya. A redescription of the metacercaria that infect Nile tilapia Oreochromis niloticus niloticus (L.) from the same aquatic environment is also presented. C. cutaneum differs from all other species of Clinostomum Leidy, 1856 in the shape of its uterus. Sequencing the rRNA confirmed the morphological similarity between adults from the grey heron and the metacercarial stage from tilapia, and a level of genetic similarity with the other previously sequenced Clinostomum spp. was observed. The need for a reorganisation of Clinostomum using both morphological and molecular methods is highlighted.