Photo: La Patilla retrieved

As the ever-deepening crisis forces Venezuelan migrants out of the country’s borders, vector-borne diseases follow them, threatening to end two decades of public health progress in Latin America and catching the attention of the world’s medical community.

Vector-borne diseases are caused by pathogens that can’t infect human beings directly, but rather than going through a third organism—usually an insect—to get to us. Malaria, chagas, dengue, zika, chikungunya, yellow fever, filariasis and countless other tropical diseases are all vector-borne. Controlling these conditions is tricky, since extensive public health campaigns aimed at reducing the number of vectors in a certain territory must be coupled with early detection and treatment programs for affected patients, creating a considerable challenge for any fairly functional health system, not to mention one hit by the worst socio-economic crisis in the Western Hemisphere’s recent history.

In a thoroughly researched review published last week in Lancet, one of the world’s leading medical journals, a group of over 60 Venezuelan and foreigner physicians and researchers reveal how Venezuela has lost capacity to deal with these conditions, and how the region is now paying the price. All while shedding some light on data that Venezuelan authorities have tried hard to hide.

A group of over 60 Venezuelan and foreigner physicians and researchers reveal how Venezuela has lost capacity to deal with these conditions, and how the region is now paying the price.

The dramatic implications of the rise of the number of malaria cases seen in the last 20 years can’t be stressed hard enough. According to the data published in Lancet, cases increased in 359% between 2000 and 2015, and 411,586 were reported only in 2017 (a 71% increase compared to 2016). These numbers show that Venezuela might exhibit the largest percentage increase in the world, beating sub-Saharan countries and severely undermining the World Health Organization’s (WHO) effort to control the disease by 2030. It also contrasts the achievements reached by other Latin American countries, a region where numbers had been dropping for the last decade.

Illegal mining has taken the disease out of its traditional hotspots deep into Bolivar State’s rainforests, spreading it across Venezuela, but also to neighboring countries Colombia and Brazil, where the numbers of cases imported from Venezuela has risen quickly. The situation is particularly worrying in the Brazilian border state of Roraima, where authors indicate that 20% of the almost 48,000 patients reported between 2014 and 2017 came from Venezuela, the situation being particularly bad in the towns of Paracaima and Boa Vista where 45% and 86% of all cases, respectively, were attributed to Venezuelan immigration.

Chagas disease is another vector-borne condition treated in the Lancet piece. Caused by the parasite Trypanosoma cruzi and transmitted by triatomines, a type of conenose bugs, it causes an initially asymptomatic condition that over the years can produce severe and irreversible cardiac and gastroenterological dysfunction in about 40% of those exposed to the parasites. In Venezuela, after decades of extensive vector control policies, seroprevalence (an indicator of a person’s exposure to the parasite) among children under ten years old, reached just 0,5% in 1998. But the data reported in the article shows that after years of underinvestment and the complete abandonment of the program in 2012, seroprevalence in children is estimated at 4,3%, a number comparable to that of 1970, with the highest rates in Portuguesa and Anzoátegui states. Nationally, seroprevalence in all age groups suggests that about 15% of all Venezuelans might have been exposed to the parasite, almost three times the percentage reported in Colombian and Ecuadorian regions where chagas is considered endemic.

Furthermore, 16 outbreaks of orally transmitted chagas (through the consumption of fruit juices contaminated with the bugs’ feces) have been reported in Venezuela between 2007 and 2018, half of them in or around Caracas, where according to researchers of the Universidad Central de Venezuela’s Institute of Tropical Medicine cited in the text, up to 76% of randomly captured bugs proved to be infected with the trypanosomes, and 60% had fed from humans at least once. Eleven cases of a particularly severe, acute form of the disease were reported by Colombian authorities between 2017 and 2018, after an outbreak erupted in Tachira earlier that year.

Endemic areas of cutaneous Leishmaniasis, another parasitic disease transmitted by sandflies, have also expanded in Merida, Tachira, Trujillo, Lara, Miranda and Sucre since 2006. Although the review’s authors claim this can be explained by unplanned urbanization and deforestation of high-prevalence areas, rather than the crisis itself. Nonetheless, the disease has already been detected in Venezuelan immigrants in Colombia.

Finally, arboviruses (viruses transmitted by arthropod vectors) such as dengue, zika and chikungunya have widely spreaded through the country, taking advantage of inefficient vector-control campaigns and the irregular water supply that most Venezuelans receive, and that forces them to store it in containers used by the mosquitoes as breeding sites. Cases of dengue fever have been continuously increasing in Venezuela since the 90s, with major epidemics occurring in 2001 and 2010.

Migration might have taken dengue to places as far as Madeira, a Portuguese island in the Atlantic Ocean that formerly was an important source of migrants to Venezuela. Since 2013, the island has received over 6,000 Venezuelan immigrants, and according to the Lancet piece, some might have taken the disease with them: A major dengue outbreak occurred that year and it was caused by a virus serotype prevalent in Venezuela.

Migration might have taken dengue to places as far as Madeira, a Portuguese island in the Atlantic Ocean that formerly was an important source of migrants to Venezuela.

Officially, about 30,000 cases of chikungunya were reported in Venezuela during 2014 (the last year with available information), but according to the review, estimations suggest the real number might be over 2 million, throwing an astonishing incidence of 6,975 cases per 100,000 inhabitants, 12 times more than the rate reported by the Health Ministry. A similar situation is seen with zika, a virus that reached Venezuela in early 2016 and that has been linked to both congenital malformations and a form of potentially lethal paralysis known as Guillain-Barré syndrome. Although no official information is available, the Lancet piece estimates that up to 80% of Venezuelan pregnant women might have come into contact with the virus at some point of their lives (not necessarily meaning their children will develop abnormalities). The number of reported cases of Guillain-Barré in Venezuela increased in 877% since the zika outbreak started.

The re-emergence of vector-borne diseases in Venezuela is the product of decades of underinvestment in the public health surveillance network, at the expense of parallel, inefficient programs; recently worsened by a decade of economic and social upheaval. The massive emigration seen in the last five years has now made this a regional problem that requires direct intervention from WHO and the Pan-American Health Organization (PAHO), in order to strengthen Venezuelan epidemiological networks.

Something that given the Venezuelan Health Ministry’s chronic negligence in this matter, seems impossible to achieve without a regime change in the country.

The alternative, as pointed out by this paper’s authors, is risking to lose the important public health achievements the region has gained after two decades of hard work and massive investment.

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