Salmonella Infection in the Caribbean Outbreak


The Salmonella outbreak became a public health concern in the mid-1980s in the Caribbean. In particular, the pathogen caused diarrhea in both the local population and tourists. One of the most important behavioral determinants is eating raw or undercooked eggs. The odds ratio of the occurrence of the disease, in this case, is the highest among other behavioral practices. Notably that “the implicated food items correlated with the predominance of cases in December and January as many of these foods are consumed more frequently in the holiday season” (Stehr-Green, 2004, p. 9). Living in close proximity to unsanitary farms is also an important social determinant.

In particular, the food safety officer identified several farms with unsanitary conditions where Salmonella samples were more common in products. Thus, people who consume eggs from these farms are more susceptible to Salmonella infection (Cardoso et al., 2021). Finally, in a laboratory study of eggs, it was revealed that “Salmonella was detected more often in shell cultures (4.6% of samples) than in content cultures (1.2% of samples)” (Stehr-Green, 2004, p. 10). This aspect identifies that eating eggs with shells or not washing eggs before eating is an important behavioral determinant of infection.

The main disparity regarding the current health issue is the imperfect reporting system in the affected countries. In particular, many healthcare professionals needed additional training for Salmonella detection and laboratory testing. Among the measures to prevent and control the disease, the need to increase the level of education of the population is indicated. Insufficient awareness of the population about the methods of spreading the infection is an important disparity factor. Additionally, not all farms have access to clean water and sufficient sanitation measures. This factor is also of key importance and acts as an aspect of disparity.

The identified determinants are directly related to the defined disparities, as they allow researchers to describe the risk factors for Salmonella infection. In particular, they include insufficient qualifications of healthcare professionals in the diagnosis of the disease and an underdeveloped reporting system. One of the most significant factors is the low level of education of the population about the existing risk factors of infection. In particular, behavioral determinants identify that the greatest chance of infection is present in groups that consume raw eggs and pay insufficient attention to washing them. Additionally, the inability to provide sanitary conditions on farms as a disparity factor leads to an increased risk of infection, which is a determinant.

Health Issue

The main risk factors for Salmonella infection in the Caribbean outbreak are eating raw or undercooked eggs (Stehr-Green, 2004). Other studies identify that direct contact with domestic animals, particularly poultry, is also a risk factor (Djeffal et al., 2018; Dang-Xuan et al., 2019). The main factor contributing to infection is the close proximity of domestic birds to the place of food production. Additional risk factors are poor hygiene and the consumption of contaminated water (Stehr-Green, 2004; Djeffal et al., 2018; Dang-Xuan et al., 2019). A key aspect of outbreak prevention is maintaining hygiene in pet and poultry farms and ensuring access to clean water. Insufficient sanitation of domestic animals and poultry houses is a major risk factor for the development of Salmonella and its transmission to humans through eggs and meat.

Salmonella is usually transmitted to humans through the consumption of contaminated food, particularly eggs and meat from poultry and domestic animals. Additionally, Salmonella can be transmitted to humans through direct contact with pets (Djeffal et al., 2018). Another important route of transmission is through drinking contaminated water (Stehr-Green, 2004; Dang-Xuan et al., 2019). It is also important that insufficient hygiene of food workers (insufficient handwashing) can cause infection transmission.

To calculate the incidence rate, it is necessary to divide the number of cases by the population at risk. Therefore, it is additionally necessary to find the size of the population that inhabited Trinidad and Tobago in each of the years. Between 1988 and 1997, the population of Trinidad and Tobago was about 1.200.000 people (1.204.000-1.259.000) (Trinidad and Tobago population, n.d). To calculate the incidence rate, it is necessary to divide the number of new cases by the population size. To find the average value for the period, you need to find the average value of the number of new cases over ten years. For the period from 1988 to 1997 in Trinidad and Tobago, the average Salmonella incidence rate was 9.08 per 100.000. The annual prevalence rate per 100,000 people is presented in Table 1; the average prevalence rate for the period from 1988 to 1997 is 0,0092%.

Table 1: The prevalence of Salmonella in Trinidad and Tobago population from 1988-1997

Year 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997
Prevalence Rate (%) 0,0043 0,0037 0,0043 0,007 0,0113 0,0095 0,0108 0,0116 0,017 0,0116

The case study report identifies that an average of 4 people per year died from Salmonella infection (Stehr-Green, 2004). To find the mortality rate, it is necessary to divide the number of deaths by the population at risk. Thus, it is necessary to divide 4 by 1.200.000, which equals 0.000003. Therefore, the annual mortality rate from Salmonella infection in Trinidad and Tobago was 0.0003%.

The case study also presents odds ratios that allow associations to be made between a potential source of infection and the disease. Thus, the strongest correlation exists between infection and eating food with raw or undercooked eggs. This means that this method of infection is the most common. Eating shell eggs is also a common potential method of infection, but the odds ratio for it is almost twice lower. Odds ratios for ground beef, powdered milk, and live chickens exposure range from 1.3 to 1.5, which identifies a low risk of infection from them. Finally, storage and consumption of eggs from the refrigerator have the lowest odds ratios. Thus, the most common potential sources of infection are the consumption of raw and undercooked eggs, as well as the consumption of shell eggs.

Levels of Prevention

The primary level of prevention is a set of actions to prevent a disease before it affects the population. In the presented case study, prevention measures include “public health education of consumers, food service establishments, and food workers and strategies for reduction of Salmonella infections among egg-laying flocks and breeder flocks” (Stehr-Green, 2004, p. 12). Additionally, in collaboration with the Ministry of Agriculture, protocols have been developed to prevent the spread of Salmonella, as well as informing egg producers. Quarterly testing of eggs for infection has also been put in place to prevent an outbreak. If an infestation is found, the flocks are retested and the infected eggs are pasteurized.

The secondary level of prevention described in the case study aims to improve screening procedures for the disease at its earliest stages. In particular, the Ministry of Health has made efforts to reduce the time required to report Salmonella cases. Surveillance Officers have been hired to whom healthcare professionals and laboratories must directly report a diagnosed disease. Additionally, cases of Salmonella contamination that could lead to infection of the population must be reported within 24 hours (Stehr-Green, 2004, p. 12). Thus, the secondary level of prevention was to accelerate the screening and reporting of the disease to start timely treatment and reduce the chance of its spread and start timely treatment.

The tertiary level of prevention is to select the most effective treatments after diagnosis. In the case study presented, the Ministry of Agriculture promoted initiatives to create antibiotics specialized in the treatment of Salmonella infection. Although antibiotics were not previously prescribed to the general population, only to severe cases of the disease, access to them has been made easier for the most effective treatment. It is also important that an educational program was organized to explain to the population how to eliminate the main symptoms of the disease. Particular focus was placed on the importance of hydration and the danger of dehydration in Salmonella infections. These aspects of tertiary prevention contribute to faster and more effective treatment and minimize the risk of infection outbreaks and the development of complications.

Measures at different levels of prevention differ in the focus of procedures that are not aimed at minimizing the risk of spreading the disease at different stages of infection. In particular, the primary level targets a wide range of possible risks, the secondary level works with improving the reporting system, and the tertiary level involves more individual cases. Thus, taken together, they address key aspects of the health issue, including poor sanitation, low levels of education among the population, and structural issues in the healthcare system.


As part of the further investigation of the health issue and the impacted population, it is important to consider whether Salmonella contamination leads to long-term health problems. Thus, the research question for future investigation is: Does Salmonella infection lead to long-term health problems? It will also be important for this study to consider what factors may be determinants of the development of long-term problems if they are identified. The observational research design is the most appropriate for this study, as it involves monitoring specific population groups over a long period of time. Within the framework of the research, it will be most important to conduct a case-control study to identify the difference in the development of long-term pathologies between the survivors of the disease and healthy patients.

Further research in this area is important as it will allow healthcare professionals to better assess the risks of infecting patients. These aspects in the future may result in the development of more effective methods of preventing and treating infection. Thus, the potential benefit of this study lies in the possibility of minimizing the impact of Salmonella on specific populations and eliminating the risk of developing possible complications.


Cardoso, M. J., Nicolau, A. I., Borda, D., Nielsen, L., Maia, R.L., Møretrø, T., Ferreira, V., Knøchel, S., Langsrud, S., & Teixeira, P. (2021). Salmonella in eggs: From shopping to consumption—A review providing an evidence-based analysis of risk factors. Comprehensive Reviews in Food Science and Food Safety, 20, 2716-2741. Web.

Dang-Xuan, S., Nguyen-Viet, H., Pham-Duc, P., Ungerm F., Tran-Thi, N., Grace, D., & Makita, K. (2019). Risk factors associated with Salmonella spp. prevalence along smallholder pig value chains in Vietnam. International Journal of Food Microbiology, 290, 105-115. Web.

Djeffal, S., Mamache, B., Elgroud, R., Hireche, S., & Bouaziz, O. (2018). Prevalence and risk factors for Salmonella spp. contamination in broiler chicken farms and slaughterhouses in the northeast of Algeria. Veterinary World, 11(8), 1102-1108. Web.

Stehr-Green, J. K. (2004). Salmonella in the Caribbean. Case study.

Trinidad and Tobago population. (n.d). Worldometer. Web.

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