Quantification of microbial risk associated with fecal exposure in a nomadic lifestyle; case study of Turbi ward, Marsabit County

Ethical consideration

Permission was sought through the board of postgraduate studies of Meru University of science and technology, The Meru University of Science and Technology Institutional Research Ethics Review Committee (MIRERC) and County government of Marsabit.

Study area

The study was carried out in the Turbi ward, North Sub-County of Marsabit County, Kenya, with a population of 23,978 (Kenya National Bureau of Statistics 2019). The populations are mostly Cushitic community practicing a pure nomadic lifestyle. The area has land mass of 10,821 km², and is located at longitude 38°22′25′′E, latitude 3°20′51′′N. Has tropical dry savanna climate. Map for Turbi ward in Northhorr sub county (Figure 1).

Figure 1. Shows sampled area of Turbi Ward.

Figure 2. CFUs from different sampled areas in Turbi Ward.

Figure 3. CFUs from milk samples from selected households.

Study design and population

The study employed a cross-sectional study design with an aspect of laboratory analysis. Samples for analysis were collected from dams, pans, camel milk and swabs from milk holding containers. The samples were then transported to the laboratory for analysis. Consent to collect water samples from dams, pans and boreholes was obtained by village elders while milk and swabs from containers consent was given by household heads.

Sampling procedure

Simple random sampling was conducted to select one village from each center totaling to five villages. Water from dams, pans and boreholes were collected while milk samples were collected from the selected households.

Sample processing

Preparation and analysis of water and milk in the laboratory

Water and milk analysis for most probable number required sterile bottles with MacConkey broth, and Durham tubes for gas collection. Each bottle with sample was appropriately labelled. The water was mixed thoroughly by inverting the bottle many times. The cap of the bottle was removed and the mouth of the bottle flamed. The water samples were then inoculated. After inoculation, the bottles were incubated at 44°C for 24 hours the samples were examined for color change and gas formation.

Biochemical identification of E. coli using Tryptone water

Positive isolates were subjected to biochemical identification using Indole test for E. coli. The test organism was inoculated in a bijou bottle containing 3 mL Tryptone water and incubated at 37°C for 24 hours.

Enumeration of E. coli CFU using colony counter

All samples that were confirmed to have E. coli were subjected to enumeration in order to calculate the colony forming unit. A serial dilution was performed up to 10⁵ for E. coli. Then 100 μL were transferred into plate count agar plates arranged from 10⁰ to10⁵ respectively. They were incubated for 24 hours at 37°C. The plate that had grown distinct colonies were subjected to counting and colony forming unit calculated. Selected plate was placed on a counting chamber and a colony pointer was used to touch the surface where the colony was had grown on the media and all the colonies will be counted. Colony forming unit was obtained by multiplying number of colonies counted times the dilution factor.

Data analysis and presentation

Data are presented using tables and bars graphs to compare microbial contamination in different villages.

Microbial analysis of water pathways

All the samples taken from all sampled villages had high E. coli bacteria, indicating extent of faecal contamination in water sources used for domestic purposes. Surface water from dams 20% (n=50) and borehole feed water tanks 20% (n=50) had high positivity of E. coli colonies. Table 1 shows the CFU of water samples. Only three samples tested negative for E. coli; these were in Okola. Turbi dam and Okola pan had high E. coli counts colonies both having high positivity of 10% and 8% (n=50) respectively (Table 1).

Microbial analysis of milk pathway

E. coli was positively identified in milk from Turbi 21%, (n=37), Shurr 19%, (n=37) (Table 2). The lowest burden was Dekuku 5% (n=37) manyattas (small settlements). Out of the 37 samples analysed, 12 tested negative for E. coli (Table 2).

Microbial analysis of various pathways

The principle finding of this study is predominance of E. coli in all sources; dam, pan and borehole fed water tanks. Environmental samples collected from the water pathways predominately were from dam, pan, trough, borehole, about 86% (n=50) of samples test positive for E.coli, an indicator of bacteria in faecal contamination. Dam, borehole fed water tanks and pans had positivity of 20% (n=50) showing high presence of E. coli colonies (Table 1). Turbi dam and Okolla pan had high E. coli colony numbers, both having high positivity of 1.05×10⁷ and 1.93×10⁴ CFU/mL, respectively, (Table 1); the acceptable E. coli in water for consumption is 10–40 CFU/mL (WHO 2020).

The high presence of E. coli detected in these sources used by Turbi, Okolla, and Kambi Nyoka villages could be attributted to that the fact that the research was conducted during the raining season and, during these periods, pastoralist communities depend solely on surface runoff water that feed the dams and pans. Water from boreholes which is retrieved by pumping appliances, such as the one in the Shurr village, are rarely contaminated, but due to poor management of storage tanks and poor hygiene during household water storage processes, tends to increase the likelihood of E. coli exposure in these source of water.

The results of this study also concur with related study done by Suraja and Raja (2020) on faecal exposure pathways, conducted in low income urban and peri-urban areas that identified contact with open drain water and produce to be the main pathways for exposure both for adults and children. There is limited information and research conducted on exposure pathways among communities that practice a nomadic lifestyle. Due to their mobile lifestyle, the nomadic community lacks basic amenities, such as toilets and safe drinking water (Mohamed 2020). Contamination of water bodies and environment by faecal matter exposes children and adults to water-borne diseases, such as cholera and dysentery.

Milk and milk products are basic foods consumed by people practicing a pastoralist way of life. Milk and milk products are also good media for bacterial growth. Any contamination to these food products affects health and general wellbeing of the population that depend on these food products. Milk samples collected from all manyattas showed contamination with evidence of E. coli. This contamination could be due to use of contaminated water to clean milking utensils and lack of hand washing before milking animals.

The consumption of raw milk is accepted in some pastoralist communities is associated with cultural beliefs and preference (Tumwine et al. 2015). A study conducted by Samwuel Majalija et al. (2020) in Nakasogola, Uganda, observed that 67.8% respondents reported never or rarely washed hands before milking animals. A related study conducted in India by Lingathurai and Vellathurai (2010) reported high presence of E. coli of 1.25×10⁷ CFU/mL in milk samples collected from farmers. This was linked to poor hygiene, handling, transportation and storage that affects quality of raw milk.

Recommendation

This study reaffirms the need for elaborate sanitation model tailored to the need of pastoralist community to reduce perennial fecal contamination of water sources for the community of Turbi ward.