**1. Introduction**

Diarrheic diseases are a serious public health issue in the entire world [1, 2]. Cholera is among the deadliest gastrointestinal diarrheic maladies in tropical areas [3–5], resulting almost exclusively from ingestion of water contaminated with *Vibrio cholerae*, but any fecal-oral pathway can potentially transmit the disease [6]. When untreated, the disease rapidly results in death, and transmission is quick within the community [2]. It is a problem because many developing countries lack resources and time necessary for confirmation and management of cholera outbreaks [7].

In the African continent, cholera has been a significant cause of morbidity and mortality [3, 6]. The disease was introduced in Mozambique from the Indian subcontinent in 1970 and became a major cause of infectious diarrhea [4, 8, 9]. Since then, the country has been facing outbreaks, particularly in Nampula Province [6]. The most severe happened during the 1990s, resulting in one third of all cases in Africa [5]. All diarrheic diseases together are the fourth major cause of death

of <5-year-old children, causing in average 13,105 demises per annum. Cholera's epidemiological profile is changed from epidemic to endemic due to the frequent outbreaks [6]. In general, there is a virtually countrywide epidemics every 5 years, but Nampula and Cuamba cities register annual cases [1], usually during the rainy season (December to June) [8]. According to Chissaque et al. [10], the last major outbreak was in 2015. Furthermore, some issues have been worsening the situation and raising increased concern. For instance, diarrhea-causing enteric bacteria are developing resistance to antibiotics [11], possibly because of overprescription.

Cholera is endemic in Mozambique, but there is very limited research on the matter. There is little information on transmission patterns and how risk factors such as non-potable water, improper sanitation, and hygiene affect the incidence, prevalence, and severity of the disease [4, 9]; there is no local protocol for treating acute diarrhea in children, the only reference being from the World Health Organization (WHO) [4, 12, 13]; little is known about the challenges, success cases, and the extent of the impact of the struggle against cholera in Mozambique [2] and the operational cost to implement a vaccination campaign against cholera [14]. If such information gaps are filled, it will be possible to substantially improve the strategy to mitigate the disease.

Gujral et al. [15] wrote an important contribution to the overall understanding of cholera epidemiology in Mozambique up to 2013, based on the national surveillance data. Though it is a good reference for researchers and scholars, there were some updates published in at least three journal articles [9, 10, 16], reports from the United Nations [17] or other organizations, and 17 presentations [1–8, 11, 14, 18–24] at the XVI Scientific Journeys organized by the Mozambican National Institute of Health [25]. This chapter aims to summarize the contributions of such publications for the current knowledge of cholera in Mozambique.

### **2. Sources and reviewing process**

The current analysis is based on updates presented during the XVI National Health Journeys, 17–20 September 2018, in Maputo City, in Mozambique. National Health Institute organized the event under the motto "Promovendo a intersectorialidade e a participação comunitária para o alcance dos Objectivos de Desenvolvimento Sustentável" [Promoting the multi-sectoral collaboration and community participation to meet the Sustainable Development Goals]. Since the beginning, in 1976, the journeys have been arguably the country's most relevant event on the matter, hosting presentations from leading health researchers in Mozambique [26].

Summaries of all presentations were then compiled to Revista Moçambicana de Ciências de Saúde [Mozambican Journal of Health Sciences]. There were 19 presentations directly or indirectly related to cholera. Some content was a follow-up of other previously published international journals, and it facilitated their interpretation. ATLAS.ti 8.1 (ATLAS.ti Scientific Software Development GmbH, Berlin, Germany) was used to analyze most information and Jamovi 0.9 (The Jamovi Project, Amsterdam, Netherlands) for meta-analysis when necessary.

Most studies on cholera in Mozambique conducted during the last decade were complementary, connected as part of a multidisciplinary approach for accompanying control campaigns led by the Ministry of Health, targeted to susceptible groups in areas where annual outbreaks occur during the rainy season [16]. At least half of the studies used data from Nampula City [23], but there were also studies in Tete, Moatize, Quelimane, Mocuba, Guruè, Metangula, Cuamba, and the country in general [1, 2, 5, 19–21]. Chissaque and Deus [20] presented, in the journeys, content directly related to a journal article published the same year [10].

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*An Update on Cholera Studies in Mozambique DOI: http://dx.doi.org/10.5772/intechopen.88431*

**3. The current situation of cholera in Mozambique**

respective analyses on the limitations and constraints.

at least 8 years, originating 67 of the isolates analyzed.

**3.2 Risk factors and health determinants**

cost of the vaccine [14].

**3.1 Etiology**

It is perhaps important to mention the group that contributed the most with presentations about cholera during the Scientific Journeys. It was the team of Baltazar and Baloi [23], from the National Institute of Health, mostly reporting on different aspects of the immunization campaign in Nampula City, 2016. Their particular presentation was focused on the vaccine coverage and acceptability, but the same group also analyzed local media coverage and people's reaction [21], evaluated environmental determinants [4] and post-campaign adverse effects [18], validated a rapid test to monitor the efficacy of the vaccine [7], and evaluated the economic

Since most publications are interconnected, based on the same campaigns and projects, they shared some constraints and limitations. They might not be explored in full depth in the following subsections. Section 5.7.3 presents more details and

The main causes of diarrhea in Mozambique, especially in children, are *V. cholerae,* rotavirus, *Shigella* spp., *Escherichia coli*, *Cryptosporidium* spp., and *Aeromonas* spp. [20]. At this stage, *V. cholerae* is well-known as the cholera-causing microorganism, even outside scholarly or scientific circles. Etiological studies are now focused on peculiarities or diversity of endemic strains in Mozambique, and how to rapidly distinguish cases of cholera from other forms of diarrhea, especially during emergency situations. The more accurate the diagnostic, the more appropriate the treatment. According to Langa et al. [16], Mozambican *V. cholerae* O1 isolates from 2012 to 2014 outbreaks are genetically closely related to strains of pandemic worldwide, unlike the Indian-born found 20 years ago. Garrine et al. [9] went one step forward by analyzing how related 75 isolated were from patients in Manhiça District Hospital from the start of the millennium up to 2012 and 3 from the Komati River. They were able to reveal four unrelated genotypes and two clonal complexes with 22 genotypes by using a multilocus variable-number tandem-repeat analysis (MLVA), and through whole genome sequencing (WGS), they detected recombination and four isolates genetically unable to produce cholera toxin. The investigators were also able to deduct that Wave 3 of the seventh pandemic [27–29] remained in the area for

It is worth mentioning *Aeromonas* spp., as Chitio and Langa [24] demonstrated that these microorganisms cause symptoms easy to confuse with cholera's, particularly during outbreaks. They detected *Aeromonas* spp. in 30 (10.4%) of 289 samples of rectal swabs from patients with suspicion of cholera during outbreaks in 2014 and 2015. The species were *Aeromonas sobria* (57%), *Aeromonas hydrophila* (20%), *Aeromonas caviae* (13%), *Aeromonas veronii* (7%), and *Aeromonas salmonicida* ssp. *salmonicida* (3%).

Environmental sanitation is important to control disease for the benefit of public health [19]. For several natural, sociopolitical, cultural, and economic reasons, Mozambique is spatially heterogeneous in terms of distribution of resources, including water, housing, their conditions [30], and certainly other features potentially affecting the transmission of cholera. Thus, one shall expect to see substantial differences in terms of risk factors and health determinants in different *An Update on Cholera Studies in Mozambique DOI: http://dx.doi.org/10.5772/intechopen.88431*

It is perhaps important to mention the group that contributed the most with presentations about cholera during the Scientific Journeys. It was the team of Baltazar and Baloi [23], from the National Institute of Health, mostly reporting on different aspects of the immunization campaign in Nampula City, 2016. Their particular presentation was focused on the vaccine coverage and acceptability, but the same group also analyzed local media coverage and people's reaction [21], evaluated environmental determinants [4] and post-campaign adverse effects [18], validated a rapid test to monitor the efficacy of the vaccine [7], and evaluated the economic cost of the vaccine [14].
