**a. Malaria**

Malaria is caused by Anopheles, which are responsible for approximately 219 million cases worldwide and more than 400,000 deaths each year. In Haiti, malaria is considered a major public health problem with a fairly large spatial and temporal distribution in the West departments and that of Grand-Anse.

*Vector-Borne Diseases and Climate Change in the Environmental Context in Haiti DOI: http://dx.doi.org/10.5772/intechopen.96037*

The following **Figure 4** is an illustration of the main sites of mosquito behaviour studies.

The country has not been able to reach its goal of eliminating malaria by the year 2020 as planned. Additional information should be generated by epidemiological studies on vector ecology in order to develop strategies to facilitate the eradication of this disease [31, 32]. In order to understand the direct and indirect impacts of climate change on malaria, the variability of malaria transmission as well as climatic and anthropogenic factors need to be analyzed. The sporogonic cycle of Plasmodium is related to the increase in air temperature and the life cycle of Anopheles is related to changes in their natural breeding habitat resulting from changes in humidity following acclimatization reactions of vegetation under climate change.

The indirect impacts of temperature change on soil moisture dynamics are important and should be balanced against the direct effects of temperature change on mosquito and parasite life cycles for the prediction and future control of malaria [29, 30].

#### **b. Dengue fever**

Dengue fever is the most common infectious disease transmitted by mosquitoes of the genus Aedes, which carry the virus responsible for the disease. Although it is a tropical viral disease, it should be noted that a dengue epidemic occurred in Madeira, Portugal in 2012. This highlighted the potential for re-emergence of dengue in Europe due to global warming and the extension of vector distribution areas due to climate change. The dengue virus is circulating in Haiti, but it is not yet recognized as a major disease in the population. In 2011, to assess the prevalence of antibodies against dengue virus (DENV), serum samples were collected from infants and young children aged 7 to 36 months (n = 166) and tested by seroneutralization tests. Serotype 1 of the dengue virus infected 40% of this study population, followed by serotype 2 (12%), serotype 3 (11%) and serotype 4 (2%).It was found that 53% of infants and young children under 12 months of age had already been infected with DENV. The seroprevalence rate against DENV increased to 65% at 36 months of age. Heterotypic antibody responses were an important component of the total dengue immunity profile [33].

In October 2012, 25 cases of dengue fever, confirmed by rapid diagnostic tests (RDTs), were detected among workers of non-governmental organizations (NGOs) in Haiti based in Leogane and Port-au-Prince to determine the extent and risk factors for dengue virus infection. Of the 776 staff members of the targeted NGOs, 173 (22 percent; 52 expatriates and 121 Haitians) participated. Dengue IgM antibodies to dengue virus (DENV) were detected in 8 expatriates (15%) and 9 Haitians (7%), and the non-structural protein DENV 1 in one expatriate. Anti-DENV IgG antibodies were detected in 162 (94%) participants (79% expatriates; 100% Haitians), and confirmed by micro-neutralization tests as specific for DENV in 17/34 (50%) expatriates and 42/42 (100%) Haitians. Of 254 nymphs collected in 68 containers, 65% were AedesAegypti; 27% were Aedesalbopictus. Few NGO workers reported taking action to avoid mosquitoes (**Table 1**) [34].

A cross-sectional study of dengue virus (DENV) and West Nile virus (WNV) transmission was conducted using standard seroepidemiological methods. Blood samples (N = 673) were collected from 278 males and 395 females from three localities in the western and southeastern departments of Haiti. Serum was tested for the presence of anti-DENV and anti-WNV immunoglobulin G (IgG) antibodies using an indirect enzyme-linked immunosorbent assay (ELISA). Anti-DENV IgG antibodies were detected in 72.1% (95% confidence interval [CI] = 68.7, 75.5) of the


*\*OR, odds ratio.*

*† Recent infection is any participant with a positive anti-DENV IgM or non-structural protein 1 (NS1) result. ‡ Significance level, p < 0.05. Univariate analysis using Fisher's exact test was used to assess risk factors for recent infection, and 95% confidence intervals (CI) were based on the modeling accounted for the sampling design. Only significant variables with a cell size of 5 or greater were retained.*

#### **Table 1.**

*Risk factors for current and/or recent dengue virus (DENV) infection in non-governmental [34].*


*Vector-Borne Diseases and Climate Change in the Environmental Context in Haiti DOI: http://dx.doi.org/10.5772/intechopen.96037*

#### **Table 2.**

*Serotype-specific antibody to dengue virus as a function of age, Haiti\* [35].*

sample population; without significant differences in seroprevalence by study site, gender or age group (see **Table 2**) [35].

There was a high prevalence of anti-DENV IgG antibodies in all age groups, including the youngest age group (2–5 years), suggesting hyperendemic transmission of DENV in the western and southeastern departments of Haiti. These results undoubtedly demonstrate the endemic nature of dengue fever in the country (**Table 2**).

#### **c. Chikungunya**

Chikungunya is an infectious disease caused by an Arbovirus belonging to the Togaviridae family, which is transmitted to humans through the bite of a mosquito of the genus Aedes, mainly AedesAegypti better known as the tiger mosquito. The chikungunya virus has been known since the 1950s when it caused major epidemics in Southeast Asia and India. The wide geographical distribution of vectors has

made it possible for the virus to emerge in many regions, as has been seen with other arboviruses, such as West Nile virus, which has been introduced and established on the North American continent since 1999. The first cases of chikungunya were detected in Haiti during April 2014, but the disease was detected in the Caribbean in St Martin as early as December 2013. Indeed, in a longitudinal cohort epidemiological study of 153 serum samples collected between 2011 and 2013 and another 61 collected in 2014, of those collected in 2014, none of the 153 samples were positive for IgG responses to chikungunya virus antigen, while 78.7% or 48 out of 61 were positive. In the cross-sectional sample, such responses were detected in 96 (75.6%) of the children and occurred at similar prevalence in all age groups [36].

Serological tests indicate that there has been a rapid and intense spread of the chikungunya virus in Haiti. The Ministry of Public Health and Population had reported a cumulative total of 39,343 cases between May 31 and June 16, 2014 in the 10 departments with an infection rate of 67% for the West Department. By mid-August 2014, more than 68,000 cases had been reported. However, after the peak at the beginning of June, the number of new cases per week had continued to decrease from over 12.000 to 315.

The disease left bad memories in the population because of the intense pain it caused through its clinical manifestations (signs and symptoms) including arthralgia, intense myalgia with sequelae that persisted for several months or even years. Although the clinical presentations of the diseases caused by these mosquitoes are similar, the arthralgia strongly suggests a Chikungunya virus infection [37].
