Epidemiology of cholera outbreak in Kampala, Uganda

Legros, Dominique; McCormick, Marie C.; Mugero, Charles; Skinnider, Marie; Bekobita, D.; Si, Okware

doi:10.4314/eamj.v77i7.46659

Cited by 23 publications

(19 citation statements)

References 3 publications

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“…In zones of endemicity, young children are vulnerable (10), and by adolescence most have serological evidence of previous exposure to V. cholerae O1 (25). During outbreaks of cholera in zones where cholera is not endemic, children and adults are equally affected by cholera (21,24). As such, children bear a very large burden of cholera globally (10).…”

Section: Discussionmentioning

confidence: 99%

Memory B Cell and Other Immune Responses in Children Receiving Two Doses of an Oral Killed Cholera Vaccine Compared to Responses following Natural Cholera Infection in Bangladesh

Leung¹,

Rahman²,

Mohasin³

et al. 2012

Clin. Vaccine Immunol.

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ABSTRACTCurrent oral cholera vaccines induce lower protective efficacy and shorter duration of protection against cholera than wild-type infection provides, and this difference is most pronounced in young children. Despite this, there are limited data comparing immune responses in children following wild-type disease versus vaccination, especially with regard to memory responses associated with long-term immunity. Here, we report a comparison of immune responses in young children (2 to 5 years of age;n= 20) and older children (6 to 17 years of age;n= 20) given two doses of an oral killed cholera vaccine containing recombinant cholera toxin B subunit (CtxB) 14 days apart and compare these responses to those induced in similarly aged children recovering from infection withVibrio choleraeO1 Ogawa in Bangladesh. We found that the two vaccine groups had comparable vibriocidal and lipopolysaccharide (LPS)-specific plasma antibody responses. Vaccinees developed lower levels of IgG memory B cell (MBC) responses against CtxB but no significant MBC responses against LPS. In contrast, children recovering from natural cholera infection developed prominent LPS IgG and IgA MBC responses, as well as CtxB IgG MBC responses. Plasma LPS IgG, IgA, and IgM responses, as well as vibriocidal responses, were also significantly higher in children following disease than after vaccination. Our findings suggest that acute and memory immune responses following oral cholera vaccination in children are significantly lower than those observed following wild-type disease, especially responses targeting LPS. These findings may explain, in part, the lower efficacy of oral cholera vaccination in children.

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Section: Discussionmentioning

confidence: 99%

Memory B Cell and Other Immune Responses in Children Receiving Two Doses of an Oral Killed Cholera Vaccine Compared to Responses following Natural Cholera Infection in Bangladesh

Leung¹,

Rahman²,

Mohasin³

et al. 2012

Clin. Vaccine Immunol.

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“…From 1994 to 1998, cholera was reported annually in Uganda [1]. In 1998, Uganda reported almost 50,000 cases with incidence throughout the country [2]. The reported incidence has fluctuated between 250 and 5,000 cases every year since 2000 (Figure 1).…”

Section: Introductionmentioning

confidence: 99%

The Burden of Cholera in Uganda

et al. 2013

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IntroductionIn 2010, the World Health Organization released a new cholera vaccine position paper, which recommended the use of cholera vaccines in high-risk endemic areas. However, there is a paucity of data on the burden of cholera in endemic countries. This article reviewed available cholera surveillance data from Uganda and assessed the sufficiency of these data to inform country-specific strategies for cholera vaccination.MethodsThe Uganda Ministry of Health conducts cholera surveillance to guide cholera outbreak control activities. This includes reporting the number of cases based on a standardized clinical definition plus systematic laboratory testing of stool samples from suspected cases at the outset and conclusion of outbreaks. This retrospective study analyzes available data by district and by age to estimate incidence rates. Since surveillance activities focus on more severe hospitalized cases and deaths, a sensitivity analysis was conducted to estimate the number of non-severe cases and unrecognized deaths that may not have been captured.ResultsCholera affected all ages, but the geographic distribution of the disease was very heterogeneous in Uganda. We estimated that an average of about 11,000 cholera cases occurred in Uganda each year, which led to approximately 61–182 deaths. The majority of these cases (81%) occurred in a relatively small number of districts comprising just 24% of Uganda's total population. These districts included rural areas bordering the Democratic Republic of Congo, South Sudan, and Kenya as well as the slums of Kampala city. When outbreaks occurred, the average duration was about 15 weeks with a range of 4–44 weeks.DiscussionThere is a clear subdivision between high-risk and low-risk districts in Uganda. Vaccination efforts should be focused on the high-risk population. However, enhanced or sentinel surveillance activities should be undertaken to better quantify the endemic disease burden and high-risk populations prior to introducing the vaccine.

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“…Immune responses against Inaba and Ogawa OSP cross-react, with higher immune responses targeting the homologous infecting serotype. Currently, a hybrid strain of V. cholerae O1 El Tor expressing classical cholera toxin (CT) predominates globally (14,15).Children under 5 years of age in regions where cholera is endemic have the highest burden of disease (16,17), although both children and adults are vulnerable during cholera epidemics (18)(19)(20). We have previously shown that household contacts of cholera patients who are under 5 years of age have a significantly higher short-term risk of acquiring cholera infection than older household contacts in the same family (21).…”

mentioning

confidence: 99%

“…Children under 5 years of age in regions where cholera is endemic have the highest burden of disease (16,17), although both children and adults are vulnerable during cholera epidemics (18)(19)(20). We have previously shown that household contacts of cholera patients who are under 5 years of age have a significantly higher short-term risk of acquiring cholera infection than older household contacts in the same family (21).…”

mentioning

confidence: 99%

O-Specific Polysaccharide-Specific Memory B Cell Responses in Young Children, Older Children, and Adults Infected with Vibrio cholerae O1 Ogawa in Bangladesh

Aktar

Rahman

Afrin

et al. 2016

Clin Vaccine Immunol

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h Cholera caused by Vibrio cholerae O1 confers at least 3 to 10 years of protection against subsequent disease regardless of age, despite a relatively rapid fall in antibody levels in peripheral blood, suggesting that memory B cell responses may play an important role in protection. The V. cholerae O1-specific polysaccharide (OSP) component of lipopolysaccharide (LPS) is responsible for serogroup specificity, and it is unclear if young children are capable of developing memory B cell responses against OSP, a T cell-independent antigen, following cholera. To address this, we assessed OSP-specific memory B cell responses in young children (2 to 5 years, n ‫؍‬ 11), older children (6 to 17 years, n ‫؍‬ 21), and adults (18 to 55 years, n ‫؍‬ 28) with cholera caused by V. cholerae O1 in Dhaka, Bangladesh. We also assessed memory B cell responses against LPS and vibriocidal responses, and plasma antibody responses against OSP, LPS, and cholera toxin B subunit (CtxB; a T cell-dependent antigen) on days 2 and 7, as well as days 30, 90, and 180 after convalescence. In all age cohorts, vibriocidal responses and plasma OSP, LPS, and CtxB-specific responses peaked on day 7 and fell toward baseline over the follow-up period. In comparison, we were able to detect OSP memory B cell responses in all age cohorts of patients with detectable responses over baseline for 90 to 180 days. Our results suggest that OSP-specific memory B cell responses can occur following cholera, even in the youngest children, and may explain in part the age-independent induction of long-term immunity following naturally acquired disease. C holera is a severe diarrheal disease that is endemic in 50 countries and associated with recurrent outbreaks and epidemics, especially in resource-limited settings (1). Vibrio cholerae can be classified into approximately 200 serogroups, and epidemic cholera can be caused by V. cholerae O1 and O139 serogroups (1, 2). V. cholerae O1 organisms can be biochemically typed into classical and El Tor biotypes. The O1 serogroup consists of Ogawa and Inaba serotypes, depending, respectively, on the presence or absence of a 2-O-methyl group in the nonreducing (upstream) terminal sugar of the O-specific polysaccharide (OSP) component of the lipopolysaccharide (LPS) (3, 4). Protection against cholera is serogroup specific, with serogroup specificity being determined by the OSP component of LPS (5-10). Previous infection with V. cholerae O1 provides no protection against cholera caused by V. cholerae O139 and vice versa (9,11,12). Ogawa and Inaba serotypes frequently fluctuate during cholera outbreaks, switching most commonly from Ogawa to Inaba (13). Immune responses against Inaba and Ogawa OSP cross-react, with higher immune responses targeting the homologous infecting serotype. Currently, a hybrid strain of V. cholerae O1 El Tor expressing classical cholera toxin (CT) predominates globally (14,15).Children under 5 years of age in regions where cholera is endemic have the highest burden of disease (16,17), although both children...

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Epidemiology of cholera outbreak in Kampala, Uganda

Cited by 23 publications

References 3 publications

Memory B Cell and Other Immune Responses in Children Receiving Two Doses of an Oral Killed Cholera Vaccine Compared to Responses following Natural Cholera Infection in Bangladesh

Memory B Cell and Other Immune Responses in Children Receiving Two Doses of an Oral Killed Cholera Vaccine Compared to Responses following Natural Cholera Infection in Bangladesh

The Burden of Cholera in Uganda

O-Specific Polysaccharide-Specific Memory B Cell Responses in Young Children, Older Children, and Adults Infected with Vibrio cholerae O1 Ogawa in Bangladesh

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