Effective conservation and management of wildlife in the current changing world, call for incorporation of infectious zoonotic diseases surveillance systems, among other interventions. One of such diseases is echinococcosis, a zoonotic disease caused by Echinococcus species. This disease exists in two distinct life cycle patterns, the domestic and wildlife cycles. To investigate possible inter-links between these cycles in Kenya, 729 fecal samples from wild carnivores and 406 from domestic dogs (Canis lupus familiaris) collected from Maasai Mara and Samburu National Reserves were analyzed. Taeniid eggs were isolated by zinc chloride sieving-flotation method and subjected to polymerase chain reaction of nicotinamide adenine dehydrogenase subunit 1 (NAD1). Subsequent amplicons were sequenced, edited and analyzed with GENtle VI.94 program. The samples were further subjected to molecular identification of specific host species origin. All sequences obtained were compared with those in Gene-bank using Basic Local Alignment Search Tool (BLAST). The study found that there were 74 taeniid positive samples, 53 from wild carnivores and 21 from domestic dogs. In wildlife, mixed infections with Echinococcus and Taenia species were identified and these included E. granulosus sensu stricto, E. felidis, T. canadensis G6/7, Taenia hydatigena, T. multiceps, and T. saginata. Domestic dogs harbored Echinococcus and Taenia species similar to wild carnivores including E. granulosus G1–3, E. felidis, T. multiceps, T. hydatigena, and T. madoquae. Taenia species of nine taeniid eggs were not identified. Majority of genotypes were found in hyena (Crocuta crocuta) fecal samples. Distribution of Echinococcus and Taenia spp. varied with hosts. Mixed infections of Echinococcus spp, T. multiceps and T. hydatigena in a single animal were common. There seemed to be existence of interactions between the two cycles, although public health consequences are unknown. The presence of T. saginata in hyena suggests scavenging of human fecal matter by the animal. In addition, presence of T. multiceps, T hydatigena, T madoquae and T. saginata in the two cycles suggested possible human exposure to these parasites. The results are important in drawing up of strategies and policies towards prevention and control of Echinococcosis and other Taenia related parasitic infections, especially in endemic areas given their potential risk to public and socio- economic livelihood.
- management wildlife
- Taenia species
1.1 Importance of wildlife conservation and management
Wildlife conservation and management is the process of caring for wild animal species and their environments from destruction, including preserving rare species from extinction. All this is done to sustain a better balance within an ecosystem as well as maintaining the beauty of mother nature [1, 2, 3]. In cases where the balance is interrupted, for example in communities where wild carnivores are killed due to wildlife-human conflicts, it may lead to overpopulation of wild-herbivores, and consequently translate into overgrazing of the available vegetation and deforestation [4, 5]. For centuries wildlife, has been reported to serve as a source of food, thus sustaining human life through provision of products such as honey and bush meat . Where strict wildlife management procedures are observed, the chances for transmission of zoonotic diseases are reduced and therefore, good health and disease-free populations . Due to improved wildlife conservation and management strategies, the economy of many countries globally has improved due to income generated from tourism attraction . Tourist visits have in turn led to enhanced social and cultural livelihood in different communities, the Maasai and Samburu of Kenya included [3, 8].
2. Challenges facing wildlife species
In Africa wildlife has faced great challenges, often attributed to human activities including encroachment into wildlife sanctuaries and loss of habitats . Other challenges include poaching and illegal wildlife trade, activities that have led to the declining numbers of wild animals’ overtime [8, 10, 11]. Besides loss of habitats, poaching, pollution, climate change and invasive species, emerging and re-emerging zoonotic diseases are increasingly featuring as a major challenge in wildlife conservation. The current wild pandemic of covid-19 is a major example of such diseases, transferable from animals to human or/and vice versa which often happen when human encroach wildlife sanctuaries, and affect the balance of Nature, for example, deforestation and modification of natural habitats as a result of land use and land cover changes is responsible for outbreak of about 50% of the emerging zoonoses .
3. Emergence of infectious zoonotic diseases
Wide range of pollutants affects wildlife health and sometimes lead to animal death. Diseases in wildlife influence several biological factors like reproduction, survival fitness and abundance of wildlife species . Often arthropods and other animal species of wildlife origin have been reported to transmit diseases including Nile fever, Lyme disease, Encephalomyelopathies, COVID-19, Bovine tuberculosis, among other zoonotic diseases. Ben (2014) stated need for humans to refrain from anthropocentric attitudes towards wildlife and learn a need for respect to ecosystems, emphasizing on major benefits that exist when the balance in nature is maintained. In their report, Vila and group of scientists reported endoparasites causing zoonotic diseases in cattle and wild animals in Europe [14, 15]. The Asian tiger mosquito (
4. Echinococcosis: a zoonotic diseases
Cystic echinococcosis (CE) is a zoonotic disease of human and animals (livestock and wildlife), caused by larval stages of tapeworms of dogs and other carnivores. The disease occurs worldwide, but is particularly prevalent under conditions of extensive livestock keeping, uncontrolled slaughter and low levels of hygiene . In sub-Saharan Africa, CE is a serious public health and economic problem in the eastern and southern parts, especially for pastoralists and nomadic communities, but reliable data are limited . Effective control is prevented by inadequate resources and limited knowledge about the epidemiology. Several Hydatid cysts may occupy space on a lung, liver or kidney making it difficult for the person or animal to breath. The parasite exists in two distinct life cycle patterns, namely the domestic and the wildlife cycles .
Humans get cystic echinococcosis after ingestion of Taeniid eggs that may have been shed through feces of domestic dogs (in the domestic cycle) and/or wild carnivores in the wildlife cycle.
In Kenya, it has been unveiled that the two transmission patterns of
5. Materials and methods
5.1 Study areas
The study was done in two cystic Echinococcosis (CE) endemic areas of Maasai Mara and Samburu National reserves. The Maasai Mara National Reserve, situated in the northern part of Tanzania’s Serengeti National Park occupies 1500 km2 . The Reserves a part of the Greater Serengeti-Mara Ecosystem which is globally popular for unique phenomenon of wildebeest’s migration. The ecosystem has suitable vegetation and climatic conditions supporting a variety of wild animals, livestock and human beings. In this case, co-existence of wild animals with pastoral communities in the area is evident .
Samburu national reserve covers about 165 km2. Human beings, livestock and wild animals in are primarily dependent on the river ‘Ewaso Nyiro’. Human and wildlife interactions are therefore a common phenomenon, with wild carnivores often preying on livestock and humans fighting back and killing the predators.
5.2 Collection of study samples and isolation of Taeniid eggs
Fecal samples of wild carnivores were collected from the environment by following signs and tracks . Similarly, freshly dropped fecal samples of domestic dogs were collected within the homesteads in the two areas. Taeniid eggs were isolated from 3 g of the fecal samples using the Zinc floatation method and subsequent microscopy identification  (Figures 1 and 2).
5.3 Sample processing
5.4 DNA isolation for PCR
Individual taeniid eggs were picked under the microscope, lysed in 10 μl of 0.02 N NaOH solution. Lysates were used for amplification of the short fragment of NADH dehydrogenase Sub unit 1 gene (
5.5 Polymerase chain reaction and gene sequencing of
Amplification of a 200 bp long fragment of
5.6 DNA sequence analysis and taeniid parasite identification
DNA Sequences were viewed and edited using the GENtle software (Manske M. 2003, University of Cologne, Germany). Clean DNA sequences were then compared with existing sequences in the NCBI GenBank using the Basic Local Alignment Search Tool (BLAST).
5.7 Wild carnivore host identification
Host specificity of all taeniid positive samples from the environment of the parks were done by a method previously described . A PCR system using primer pairs forward 5’-TCATTCATTGA(C/T) CT(C/T) CCCAC(C/T) CCA-3’and reverse 5’-ACGGTA(A/G) GACATA(A/T) CC(C/T) ATGAA(G/T) G-3′ for primary reaction and a secondary reaction with primer pairs forward CA(C/T) CCAA(C/T) ATCTCAGCATGAA and reverse 5′-(G/T) GC(G/T) GTAGCTAT(A/T) ACTGTGAA(C/T) A(A/G)-3′ were used to amplify partial fragment of the
Echinococcusand Taeniaspp. in wild carnivores of Maasai Mara and Samburu national reserves
A total of 729 fecal samples of wild carnivores from Maasai Mara (387) and Samburu (342) were screened for
DNA sequence analysis of the t
|Park||Animal host||n taeniid positive / n samples||n taeniid positive PCR / n eggs screened|
|Unidentified host||4/342||17/60||9 |
|Maasai Mara||17/387||61/197||41 |
|Unidentified host||4/387||8/48||3 |
6.2 Confirmation of wild carnivore hosts origin of
In addition to signs and tracks used in identifying the source of fecal samples in the field, the actual host origin of the 53 taeniid positive samples (26 from Maasai Mara and 27 from Samburu) were confirmed by PCR and DNA sequencing of the cob gene. The cob DNA sequences indicated the involvement of
Echinococcosisand Taeniaspp. in the domestic settings in areas around Maasai Mara and Samburu national reserves
In the vicinity of Samburu National Reserve, 406 fecal samples from domestic dogs were collected; from 21 samples, 304 taeniid eggs were isolated. Ninety-two of the 304 eggs were positive on
Human encroachment into wildlife sanctuaries has augment domestic-wildlife interactions thereby raising the risk margin for transmission of zoonotic diseases. Reduced interactions between human and wild animals by putting in place strict wildlife conservation and management legislations and strategic measures will reduce the burden of zoonotic disease transmission . Population density in wildlife areas may occur in cases where management strategies include introduction of new animal species, which often result into introduction of new strains of zoonotic diseases, amidst improving number of animal population . Wildlife movements often facilitate transfer of different disease strains from one point to the other, with an example of the wildebeest migration occurring every year from Serengeti to Maasai Mara . While the migratory behavior is termed as a big economic gain due to increased tourist attraction for both countries, transmission of new strains that can cause extinction of wild species is possible. This is evidenced by a report in 2014 on existence of
Zoonotic diseases have caused advanced effect especially in low and middle-income countries . On average, up to 40% deaths occur in Africa due to infectious diseases, most of which are zoonotic . These diseases have been reported to not only cause animal or human sickness but have led to deaths and major economic loses [37, 43]. Echinococcosis, a neglected zoonotic disease, has been reported to have highest prevalence in Kenya [30, 44]. It is hypothesized that the disease transmission could be minimized by improved wild conservation management systems in the country, since this has been seen to work well as reported in previous studies [43, 45]. Most wildlife sanctuaries are unfenced, and cattle are observed often at the heart of the protected areas, and wild animals in human homesteads . This is equally interlinked with human bad slaughter behavior, where condemned offal is offered to domestic dogs, and with wild animals marauding at night, they may access and feed on this offal. This, consequently, leads to transmission of zoonotic diseases including Echinococcosis. The only reliable cure for Echinococcosis is a total removal of hydatid cyst, which is an extremely expensive undertaking, which calls for a specialized surgeon. Emergence and re-emergence of
During material sampling, it was observed that livestock herding inside the Maasai Mara National Reserve, took place at night as such the accompanying dogs might have access to carcasses of preyed animals. In both reserves the ‘lion strain´
Transmission overlap of
Increased infection of the
Inadequate data on wildlife-human related infectious diseases has reduced preparedness against disease outbreak in Kenya. More studies on problems relating to wildlife diseases, determining the presence of such diseases, their prevalence and their impact on wildlife conservation and management are inevitable. Existing wildlife management systems are deficient of disease surveillance component, and this has led to human deaths and animal loses to zoonotic infectious disease. Disease transmission between the human-wildlife cycle is a generally gray area to most stakeholders, making disease management strategies difficult. Growth in human population is causing great challenges in environmental conservation management. Changes observed include wildlife habitat change, which has adversely caused ecological changes as well as increased emergence and re-emergence of zoonotic infectious diseases. Based on the findings of this study, it can be hypothesized that if proper wildlife management systems including disease surveillance systems are observed in Kenya, wild animal population will increase, the rare species will be free of illnesses, and human mortalities caused by zoonotic diseases will decrease. There is an overlap in occurrence of
The authors acknowledge the support of Lynn Nkatha who assisted with field sampling and laboratory analysis. The authors further acknowledge financial assistance by cystic Echinococcosis in Sub-Saharan Africa Research Initiative.
Ethical permission to conduct this research was granted by Kenya Medical Research Institute’s Ethical Committee, animal care and use committee and Meru University of Science and Technology Institutional Research Ethics Review committee (MIREC-035-2017). Permission to collect samples from Maasai Mara and Samburu National Reserves was granted by Kenya Wildlife Services.