Reliable information is of paramount importance towards adequate monitoring and delivery of health care services.1 It is already established that the backbone of a successful disease control program is a strong disease information system as it not only provides the information essential to run the program satisfactorily but also lends support to different decision-making including allocation and rational use of resources.2

Failure of disease control programs has been mainly attributed to lack of credible and evidence-based decision making in health sectors.2,3 Other obstacles were outdated, incomplete and incomprehensible health related data.

To overcome all these hindrances, in 1994 the Brazilian Government introduced a nationwide disease information system for notifiable diseases, the SINAN (“Sistema Nacional de Agravos de Notificaçäo”).2,4

In the year 2004, the Brazilian Ministry of Health stated the objectives of SINAN as to diagnose any health-related occurrences in a population, to assess the associated risk factors, and to provide information to identify specific epidemiological situations in a given geographic area.2,5 The systematic information provided by SINAN is stated to be decentralized so that all health professionals and the community may have access to it. Thus, it plays a pivotal role in not only planning, and prioritizing of objectives but also in successfully implement, monitor and evaluate health related interventions.2,5

According to a 2008 WHO report, in developing countries of all diseases infectious diseases such as HIV/Aids (5.2%), malaria (4%) and tuberculosis (2.7%) were are the prevailing ones.2,6 The report also mentioned that the so-called neglected tropical diseases (NTDs) were also quite common.7,8

According to a report published by the International Organization for Migration in 2009, around 3% of the global population are migrants of which 200 million people are documented as international migrants and around 26 million people are estimated to be internally displaced in 52 countries.9 Especially in the past 50 years, huge number of people have been forced to migrate from their own countries to other countries due to various causes (especially due to socio-economic unrest, war, etc.).10–12

In 2004 Saker et al. published in their report that population mobility might lead to several health-related negative consequences affecting the migrant population, the host population, or both.13 The most significant impact of migration is the spread of infectious diseases. Most of the epidemics in human history occurred due to population migration either as consequence of war or of a complete change in the whole society.14 Thus, the spread of infectious disease from one country to other countries remains the most important concern for international organizations.15 The black death (bubonic plague) in Europe most likely occurred due to conflict with Asia minor and then it spread rapidly through trade routes.

The close association between migration and emergence of diseases, both in the host and the migrant population, can be explained by several factors. Firstly, the unfavourable environmental or social conditions which led to migration of the population in the first place like poverty, overcrowded settlements, poor economic infrastructure, and collapse of health care, scarcity facilities, lack of sanitation, safe and potable water, and education, etc. Secondly, the entire process of migration from one country to another might make the migrating population susceptible to diseases, as the risk of emergence of infectious diseases care increases because of lack of proper sanitation, availability of safe drinking water, scarcity of food leading to malnutrition, overcrowding, etc. Even after reaching the host countries, the migrant population might remain susceptible to various infectious diseases especially due to overcrowded shelters or refugee camps, and poor availability of food, potable, water, and health care facilities.

According to a 1994 report of the US Centers for Disease Control and Prevention around 50,000 people died due to cholera when leaving Rwanda migrating to Zaire. Similarly, incidences of malaria outbreaks in the refugee camps of Afghanistan and Pakistan are well documented.16 In 1999 Rowland et al. described the occurrence of cutaneous leishmaniasis among one third of the Afghan refugees in Pakistan.17

Sometimes contact with newer populations (host), newer microbes, vectors, cultural changes, behavioural and lifestyle changes might again increase the risk of infection in the already vulnerable migrant population. Several atypical vector-borne infections especially louse-borne diseases like epidemic typhus and relapsing fever are commonly prevalent in refugee camps and are associated with high fatality rate. Moreover, overcrowding in poor sanitary conditions might lead to emergence of atypical infections and multidrug resistant strains of common microbes.

Currently, the poor socioeconomic status of Venezuela has driven thousands of its citizens to migrate to different countries including Brazil. Incessant entry of Venezuelan migrants to Brazil has led to several socio-economic issues including health related issues. Thus, regular epidemiological surveillance, especially for infectious diseases, of the migrant Venezuelan and the local host population is essential to prevent outbreaks.

The objective of this study was to evaluate the emerging infectious diseases among Venezuelans immigrants in Brazil and to assess the importance of SINAN for epidemiological surveillance in the same population.

The study was a three-year retrospective observational study covering all infectious diseases reports between 2015 and 2017.

Total number of medical appointments in the three years (2015–17) was 6252, of which 3553 (56.8%) were sought by Brazilians and remaining by Venezuelans (Table 1 and Fig. 1). No prominent pattern was observed for Brazilian residents; however, the number of Venezuelans seeking medical care increased over the time from January to August followed by small drop during the later months of the year.

Fig. 1.

Number of medical appointments sought each month from 2015 to 2017.

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In 2017, out of those who sought dental care 1525 (70.24%) were Brazilians and the remaining were Venezuelan migrants (n = 646) (Table 1). Still in 2017, the number of dressings provided was higher for Venezuelans (n = 518) than for Brazilians (n = 60) (Table 1). In addition, 378 Venezuelans required nebulization and 384 required injectable drugs, numbers much higher than the 23 and 62 Brazilians, respectively (Table 1).

Both Brazilians and Venezuelan migrants reported all the evaluated infectious diseases namely tuberculosis, STIs, HIV/Aids, syphilis, hepatitis, and leishmaniasis. Majority of the reports were for STIs and of the 729 STI cases 396 were reported by Brazilians and 333 by Venezuelan migrants in Brazil. However, the numbers of reporting for each disease varied between the two groups (Table 2). There were more cases of tuberculosis, HIV/Aids, and leishmaniasis among Venezuelan migrants (tuberculosis = 9; HIV/Aids = 25; lesishmaniasis = 207) than among Brazilians (tuberculosis = 7; HIV/Aids = 8; for lesishmaniasis = 65) (Table 2). Nonetheless, there were reports of STIs and hepatitis (STIs = 396; hepatitis = 39) among Brazilians than among Venezuelan migrants in Brazil (STIs = 333; hepatitis = 1) (Table 2). Despite the differences in the numbers of reporting between the two groups for each infection (except for syphilis; four in both groups), only for hepatitis and HIV/Aids the differences were significant (p = 0.046 for both infections).

Malaria screening for residents was usually done during the period of March–June, but there was an increase in the number of screening in August 2016 (Fig. 2). In 2016, a higher proportion of screened people for malaria was positive during first half of the year, whereas in 2017 there were more malaria cases reported at the end of the year (October–December) (Fig. 3).

Fig. 2.

Number of people tested for malaria each month from 2015 to 2017.

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Fig. 3.

Percentage of malaria positive case each month from 2015 to 2017.

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Venezuela was once considered among the leading countries of the Latin America regarding vector borne diseases and strong and efficient public health related policies.18,19 It was considered the first country to eradicate malaria following a very successful insecticide spraying campaign.19 However, there has been a rise of vector borne diseases in Venezuela. Among the many attributing factors for this crisis, shortage/poor supply of insecticides, antiparasitic drugs, and fuel are the major factors along with widespread malnutrition, collapse of the existing health system, poor epidemiological surveillance and almost no reporting of infectious diseases cases.20,21 Besides vector borne diseases, viral infections especially arboviral diseases like dengue, chikungunya, and Zika are on the rise.22 One of the most important reemerging parasitic diseases in Venezuela is malaria; there is almost three-fold increase in the incidence of malaria cases since 2014.18,23 Besides malaria, Chagas disease and leishmaniasis are the other two vector borne diseases which are posing severe threat to Venezuela.24,25

Currently, with political unrest and collapse of once thriving economic system, the health care system of this country has also collapsed. Lack of jobs, economic stagnation, high inflation, high rate of crime, poor availability of day amenities have led millions of Venezuelan citizens to migrate from their own land to other Latin American countries including Brazil.18

Migrant populations as such usually suffer from different health related problems due to travelling in unhygienic conditions, lack of food, potable water, overcrowding, poor medical care, etc. In addition, settlement in the new country might prove very difficult especially if the number of migrants exceeds the capacity of the hosting country. The number of Venezuelan migrants to Brazil had a striking increase each passing day and Brazil has started to take humanitarian steps for the Venezuelan migrants. Among all the other issues, health related issues are of immense importance as there are possibilities that many of the infectious diseases might spread from these Venezuelan migrants to the locals.

In this retrospective observational study we have assessed the importance of the Brazilian health-related information system (SINAN) regarding surveillance of certain infectious diseases in the municipality of Pacaraima between 2015 and 2017 where huge numbers of Venezuelan migrants have taken shelter by collecting data.

Data analysis revealed that about equal number of Brazilians and Venezuelan migrants were seeking medical attention, but Venezuelan migrants seeking treatment (both medical and dental) seemed to be on the rise (Table 1). Reporting of HIV/Aids cases were significantly higher among Venezuelan migrants in Brazil (p = 0.046) and those of hepatitis was significantly higher among Brazilians (p = 0.046) (Table 2).

The number of malaria positive cases were far greater among the Venezuelan migrants in Brazil (n = 340, 1262, and 943 in 2015, 2016, and 2017, respectively) compared to Brazilians (n = 170, 169, and 285 in 2015, 2016, and 2017, respectively) (Table 3).

Thus, it is evident that the incidence of infectious diseases especially malaria is significantly higher in Venezuelan migrants.

In line with the present study, Tuite et al. have also shown the implication of Venezuelan migrants on emergence and re-emergence of previously controlled infectious diseases like tuberculosis, malaria, diphtheria, measles, etc. and on subsequent outbreaks of these diseases in host as well as migrant populations.26

Pavli et al. published a systematic review including all the published articles (using PubMed search and published between 2003 and 2016) on health problems (both communicable and noncommunicable) in migrants and refugees coming to Europe. Like our study, they also noted that the burden of diseases due to population migration cannot be ignored and underscored the need for a multidisciplinary integrated approach would be best for both the migrant and the host population.27

Another interesting finding of this study is the number of live births reported among Brazilians and Venezuelan migrants in Brazil (Table 4). The number of live births among Brazilians (80, 91, and 77, in 2015, 2016, and 2017, respectively) were quite high compared to those among the Venezuelan migrants to Brazil (17, 32, and 45, in 2015, 2016, and 2017, respectively) (Table 4). This suggests probable lack of proper antenatal medical care among the migrant population compared to local people. However, as the number of live births is increasing among Venezuelan migrants in Brazil it suggests that pregnant migrant women are benefiting from better health care they are receiving in Brazil.

Evaluation of emergence of infectious diseases among Venezuelan migrants in Brazil, the incidence of several infectious diseases like malaria are significantly higher in the Venezuelan population compared to local Brazilian people. Also, the importance of the SINAN system for epidemiological surveillance in both migrant and host populations cannot be underestimated.

The authors declare no conflicts of interest.