Occurence of Culturable Vibrio cholerae from Lake Victoria, and Rift Valley Lakes Albert and George, Uganda

Abstract

Vibrio cholerae, a bacterium that causes cholera, poses a human health risk when consumed via untreated or contaminated water. Monthly investigations into the presence of V. cholerae from Lakes Albert, George and Victoria were conducted, with the goal being to examine the relationship between the occurrences of V. cholerae with various water quality parameters at fish landing sites in major water bodies in Uganda. The pH, temperature and electrical conductivity were measured at three fishing sites in each of the three study lakes; namely Gabba in Lake Victoria, Butiaba in Lake Albert and Kayanzi in Lake George. The pH values varied from 7.76 to 9.36 at Butiaba, 8.68 to 9.85 at Kayanzi and 6.6 to 9.88 at Ggaba. The temperature ranged from 17.9 to 32.3 °C at Butiaba, 22.5 to 29 °C at Kayanzi and 18.2 to 30.5 °C at Ggaba. The electrical conductivity ranged from 129.2 to 984 μS cm−1 at Butiaba, 658 to 1090 μS cm−1 at Kayanzi and 119 to 218 μS cm−1 at Ggaba, for Lakes Albert, George and Victoria, respectively. Enrichment techniques were used to detect culturable V. cholerae on TCBS culture media. Seventy‐five (75%) of the samples (n = 90) were positive for V. cholera. The occurrence of V. cholerae was positively associated with water quality parameters over the 10‐month period of study. Vibrio cholerae was more frequently detected during the dry season (warmer) than during the wet season. These study results suggest the investigated study lakes are natural reservoirs for V. cholerae.

The quality of drinking and domestic water from the surface water sources (lakes, rivers, irrigation canals and ponds) and springs in cholera prone communities of Uganda: an analysis of vital physicochemical parameters

“…Hence, more efforts are required to promote safe water access in Uganda to attain the WHO cholera elimination target [25] and SDG 6 by 2030 since 26% (36/135) of mean physicochemical water tests did not meet WHO drinking water quality standards [53]. These findings together with those of the previous studies which demonstrated the presence of pathogenic V. cholerae in the same water sources [22,23,76] should guide stakeholders to improve access to safe water in the Great Lakes basins of Uganda holistically. Thus, measures such as promotion of use of safe water (using water disinfection), health education, sanitation improvement and hygiene promotion that address both the water bacteriological contents and physicochemical parameters should be considered in both the short and medium terms.…”

Environmental Surveillance of Vibrio cholerae O1/O139 in the Five African Great Lakes and Other Major Surface Water Sources in Uganda

“…The absence of V. cholerae O1 suggests that although cholera outbreaks are common in the communities near the major lakes and rivers in Uganda, these lakes may not be the source of pathogens for repeated cholera outbreaks and are unlikely to be reservoirs for V. cholerae O1 as pointed out in earlier studies in sub-Saharan Africa ( Bompangue Nkoko et al, 2011 ; Kaddumukasa et al, 2012 ) that used less definitive methods for pathogen detection. It seems more likely that the observed cholera outbreaks in Uganda could be due to other factors, such as human interaction from cholera endemic communities and outbreak affected areas leading to cross-border infections ( Baluku et al, 2015 ; Bwire et al, 2016 ), traveling from cholera affected areas as happened in Juba, South Sudan ( Ujjiga et al, 2015 ), since most of affected area were along busy international crossing points but also climatic factors could have contributed ( Rebaudet et al, 2013 ).…”

“…One possible hypothesis is that the observed distribution of cholera along the major lakes in Uganda is that the lakes and the other surface water sources (rivers, wells, ponds, etc.) are environmental reservoirs for pathogenic V. cholerae responsible for cholera epidemics, as documented in Asia ( Cabral, 2010 ; Wang et al, 2010 ; Lutz et al, 2013 ; Dalusi et al, 2015 ), and in epidemiological studies conducted in sub-Saharan African ( Bompangue et al, 2008 ; Bompangue Nkoko et al, 2011 ; Kaddumukasa et al, 2012 ). It is possible that due to poverty, low level of awareness and inadequate access to safe water and sanitation, communities located along these surface water sources use water from these surface water sources without disinfection.…”

“…However, no comprehensive environmental study has been conducted on the various surface water sources in cholera-affected communities in Uganda to establish the presence of V. cholerae . Two studies attempted to document V. cholerae in Ugandan surface water sources, but these studies focused on few water sites on L. Victoria and the three Rift Valley lakes namely, L. George, Edward, and L. Albert ( Kaddumukasa et al, 2012 ; Bagalwa et al, 2014 ). These earlier studies identified culturable V. cholerae but did not carry out agglutination tests to determine if they were epidemic serotypes O1 or O139.…”

Volcanic activity controls cholera outbreaks in the East African Rift

“…Water temperature, pH, electrical conductivity, and dissolved oxygen potentially regulate V. cholerae [20,37,38]. Over the 2007-2012 period, these parameters were measured twice per month in surface water collected in the lake near Ishungu.…”