*3.3.2 Prevalence, impact, and susceptible groups*

Since most studies presented at the XVI Health Journeys were follow-ups of ongoing studies, they all tended to miss some details, and some were complementary to each other. For instance, the studies after the 2015 outbreak of cholera in Nampula explored different perspectives on the problematics [4, 6–8, 14, 18, 22, 23]. **Table 1** shows some epidemiological data recorded after 2013. These are just some examples because it would be redundant to include some papers, particularly the studies conducted in Nampula. Still, there is plenty of information worth sharing.

The studies did not explain the dynamics of how the disease is spread during non-epidemic periods because virtually all were conducted during outbreaks, or at least based on them, though it might not differ much from times of outbreak, especially because the area is endemic. Phenomena such as heavy rain and natural catastrophes certainly work as amplifiers of the disease severity by increasing people's exposition to untreated water [3, 20, 39–42]. Yet, it would be a good idea to study the risk factors and disease determinants during times of low prevalence because it would, for instance, minimize the need for researchers to work under pressure or "under budget" because of non-research-driven priorities [43], avoid panic or undesirable reactions from study subjects, and perhaps be easy to prevent outbreaks or lower considerably their impact on public health. On the other hand, outbreak investigations are crucial to ensure proper intervention. Thus, the information below represents outbreak-related scenarios but somehow the best lead so far of the country's reality with or without an outbreak.

According to **Table 1**, the country's cholera fatality rate (CFR) in 2015 was 0.7%. This value is low, within the range 0–15.8% of the Global Health Observatory (GHO) in 2016, published by the World Health Organization [38]. According to the GHO, 22 countries had CFR > 1%, and only Niger, Zimbabwe, and Congo had CFR > 5%. Even the global (1.8%) was higher than Mozambique the previous year during the outbreak. Such low fatality rate was likely due to a very fast and effective response in terms of vaccination, treatment [11, 23], and other measures such as health education and support in sanitation [8, 17]. Cholera is highly virulent but also easy to treat and there is vaccine [44]. The fatality rate observed in Nacarôa (2%) was not far from the global, and it seems reasonable to expect such kind of fluctuations in a considerably small sample. It should be also reasonable to expect a value slightly higher than average in endemic areas.


#### **Table 1.**

*Cases of cholera recorded in the decade so far.*

It is general knowledge that cholera is spread through water and improper sanitation is a major risk factor for transmission. Thus, the disease deeply related to poverty in several ways including obviously the lack of resources for prevention or treatment and limitations in education or information. It is intuitive that the most susceptible are people living in highly crowded suburban areas when people have little access to clean water, or in rural settings, when people directly consume water from lakes or rivers without any treatment. People living around Lake Niassa use it for domestic purposes [5]. This is the reality in several areas of Mozambique. This must be understood on top of any specificity of the studies explained or discussed in this subsection. It must be implicit that all the studies' target populations were susceptible to cholera.

The research team of Baltazar et al. [23] belongs to the National Institute of Health, and they conducted most studies related to the vaccination campaign in Nampula City, 2016. In the particular study cited, they focused on inhabitants over 1 year old living in the city's six most susceptible neighborhoods, mentioned in Section 5.4.1 (Geographical distribution). People from surrounding areas are also at risk [4] because of mobility and interaction with residents of the endemic neighborhoods or exchange of food or drinks coming from such zones.

Children are the most susceptible to diarrheic diseases in general [11, 20] perhaps because of their immunity still under development, their unawareness of the bacterial load in the untreated water, and their behavior. In reality, they have always been the priority and focus of the vaccination campaigns [10, 45]. Among 1910 children hospitalized with acute diarrhea from May 2014 to December 2017, Salência et al. [11] found that <1-year-olds were the most affected and 19 infants (2.4%) had *V. cholerae*. The majority (58%) were male, but it seems that the proportion male/female always gravitates around 1:1 [1, 11, 22]. Mesa et al. [1] analyzed 128 processes of patients with acute diarrhea in Mocuba District Hospital, admitted during June and July 2015 in the local hospital. According to the authors, all patients presented symptoms consistent with cholera, but, despite their convictions, there was no confirmation, and they based their conclusions on clinical data (aqueous stool, vomit, and fever). In any case, all were below 16 years old in which 41% were below 5 years and 4% of the cases ended in decease. Differently, Paulo et al. [22] found 68% of individuals over 15 years old among 135 cases of cholera in the Center for Treatment of Diarrheic Diseases in Nacarôa District, recorded from 12 to 28 November 2017. The difference is likely due to a fact mentioned by the authors that none treated the water before consuming and the majority (64%) used well water. One has to imagine that the entire household uses the same water source and all the members have nearly the same level of exposition if it is contaminated, independently of the age and behavior of each individual. The age or sex differences might be a reflection of the actual sociodemographic profile of the community.

#### **3.4 Diagnosis**

There is little novelty on diagnosis in Mozambique since the beginning of the decade. It is perhaps worth mentioning that during the 2016 massive vaccination campaign in Nampula, Dengo-Baloi et al. [18] performed a rapid test to verify if it could be an alternative to the culture-based standard, as the latter takes 48 to 72 hours and the rapid test would take approximately 6 hours. They used an alkaline peptone water (APW) enrichment method, but they did not specify the origin of the kit. It was likely Crystal VC RDT (Span Divergent, Mumbai, India), previously used by George et al. [46] in Bangladesh and Ontweka et al. [47] in South Sudan. According to the latter, it is also considerably inexpensive. Dengo-Baloi et al. [18]

**139**

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

*3.5.1 Overview, prophylaxis, and awareness*

with limited resources.

**3.5 Control strategies**

observed exactly the same results using the standard method and the rapid test for 75 samples, demonstrating its efficacy as a good alternative for the standard in areas

Cholera control strategies in Mozambique have been changing over time, perhaps due to governmental priorities, an increasing knowledge, or resources available. Regarding Mozambique, it is important to keep in mind that Mozambique has undergone major political changes, there have been conflicts, including armed, natural calamities such as drought, floods, typhoons, economic crises, and fluctuations. All these phenomena resulted in mobility or affected people's livelihoods, changing the dynamics of access to resources, including potable water, ultimately impacting public health. This ever-changing environment has been determining, at a certain extent, the way the government deals with the epidemics of infectious diseases, including cholera. Chissaque et al. [20] mentioned some key actions of the government's strategy: vaccination, health education, introduction of zinc and salts for oral hydration, improvement of basic sanitation (construction of latrines and access to potable water), and organization of national health weeks. Dengo-Baloi et al. [18] added vigilance among the measures, and Vanormelingen et al. [17] said that the government coordinated a real-time mapping of the epidemic and supported social mobilization with the assistance of the United Nations Children's

Fund, World Health Organization, and Médecins Sans Frontières (MSF).

or use more effectively the channels to communicate with the residents.

munity from 2 to 9 November 2016 [18, 23].

After vaccination, there were adverse effects such as abdominal pain, nausea, and diarrhea, but none seemed severe enough to require any medical assistance [18]. The National Institute of Health organized a vigilance of postimmunization adverse effects in nine healthcare units, and, according to Dengo-Baloi et al. [18], there were eight cases reported after the first round of vaccination, three during the second, and one case during both rounds. Yet, there were certainly more cases because Baltazar et al. [23] reported adverse effects in 47 people of 451 interviewed after receiving vaccination. A possible explanation for the discrepancy between both studies is the fact that PIAE vigilance recorded mostly cases that occurred 24 h after vaccination, and it was based on records from healthcare units, while the other study was based on inquiries directly to randomly chosen individuals from the com-

The most relevant actions in the last decade are perhaps related to the Ministry of Health's implementation of vaccination campaigns using Shanchol™ (BivWC, Shantha [48], Ranga Reddy District, Telangana, India) in Nampula City's six most vulnerable neighborhoods, in October 2016 and also the subsequent years [4, 10, 21]. It was in response to the outbreak in 2015, and the strategy was to deliver the vaccine door to door in two rounds [23]. Paulo et al. [22] mentioned another outbreak in November 2017, but it did not seem as severe. The 2016 campaign was strategically set to cover 193,403 individuals and prevent the expansion of cholera to less affected areas [4, 18]. Though the first round only covered 69.5% of the target population, and the second covered 51.2%, Baltazar et al. [23] considered the experience as a success and shared the belief that similar strategies can have more adherence in urban settings when there is no emergency. Considerably low adherence was mostly because many people were not at home during the campaign, and 17.3% of 636 people enquired said that they were unaware of the campaign. The situation was similar in the following 2 years [21]. Thus, it is important to improve

observed exactly the same results using the standard method and the rapid test for 75 samples, demonstrating its efficacy as a good alternative for the standard in areas with limited resources.
