H5N1

Climate change, crime and political chaos: A deadly mix in Honduras dengue epidemic

Via The New York Times: Climate Change, Crime and Political Chaos: A Deadly Mix in Honduras Dengue Epidemic. Excerpt:

CHOLOMA, Honduras — More than 400 people died this year as one of the worst dengue epidemics on record swept through Central America — a type of outbreak that some scientists and public health officials are warning is likely to become more frequent and more widespread because of climate change.  

But while climate change is threatening to increase the spread of dengue worldwide by expanding the range of the mosquitoes that carry the virus, the disease has already found an especially fertile breeding ground in Honduras, for reasons that go beyond the environment.  

In Honduras, which accounted for more than 40 percent of the dengue deaths in Central America this year, according to the Pan American Health Organization, the effects of climate change have been compounded by government dysfunction, political tumult and public apathy. 

Dengue has hit the country hard. This year, it had more than 107,000 cases of the viral disease — more than 13 times the number recorded last year — and at least 175 deaths. In 2018, only three people in Honduras died from the disease, according to the Pan American Health Organization.

Honduras’s notorious criminality has worsened matters, too, as public health teams, already stretched thin by budget cuts and a lack of trained personnel, have been blocked by gangs from entering some of the most severely afflicted neighborhoods to educate residents and fumigate against mosquito infestations.  

Dengue is transmitted to humans by a type of mosquito called Aedes, which thrives in urban areas of the world’s tropical and subtropical regions. Tens of millions of cases occur each year in more than 100 countries, and symptoms may include fever, internal bleeding and shock. Inadequately treated, the illness can quickly kill. 

In Honduras, health officials trace the start of the current epidemic to the fall of 2018. The number of incidents then rose sharply during the first half of 2019, hitting a peak this summer before falling off as the year ended. A nationwide health emergency declared in July by the administration of President Juan Orlando Hernández remains in effect.  

The outbreak struck during a time of political turbulence in Honduras, with violent street protests against Mr. Hernández and calls for his ouster. Some of the protests have been driven by fears the government planned to privatize the health and education sectors. 

The nation also suffers from high murder rates and widespread poverty, which have combined to drive tens of thousands of Hondurans in recent years to emigrate, with many trying to make it to the United States.  

The dengue outbreak has met little resistance from a public health system gutted by budget cuts and pervasive corruption, analysts and officials said.  

“It’s a collapsed system, an inefficient system,” said Ismael Zepeda, an economist with Fosdeh, a research group in Tegucigalpa, the capital.

Mosquito sterilization offers new opportunity to control chikungunya, dengue, and Zika

WHO has published Mosquito sterilization offers new opportunity to control chikungunya, dengue, and Zika. Excerpt:

A technique that sterilizes male mosquitoes using radiation will soon be tested as part of global health efforts to control diseases such as chikungunya, dengue, and Zika.  

The Sterile Insect Technique (SIT) is a form of insect birth control.  The process involves rearing large quantities of sterilized male mosquitoes in dedicated facilities, and then releasing them to mate with females in the wild. As they do not produce any offspring, the insect population declines over time. 

The Special Programme for Research and Training in Tropical Diseases (TDR) and the International Atomic Energy Agency (IAEA), in partnership with the Food and Agriculture Organization of the United Nations (FAO), and WHO have developed a guidance document for countries that have expressed interest in testing the Sterile Insect Technique (SIT) for Aedes mosquitoes.  

Half the world at risk of dengue 

“Half the world’s population is now at risk of dengue,” said Dr Soumya Swaminathan, WHO Chief Scientist. “And despite our best efforts, current efforts to control it are falling short. We desperately need new approaches and this initiative is both promising and exciting.”  

In recent decades, the incidence of dengue has increased dramatically due to environmental changes, unregulated urbanization, transport and travel, and insufficient sustainable vector control tools and their application.   

Dengue outbreaks are currently occurring in several countries, notably on the Indian sub-continent. Bangladesh is facing the worst outbreak of dengue since its first recorded epidemic in 2000. The South Asian nation has seen the number of cases rise to over 92,000 since January 2019, with daily admissions peaking at more than 1,500 new dengue patients in hospitals in recent weeks and is one of the countries to express interest in the Sterile Insect Technique. 

Diseases transmitted by mosquitoes such as malaria, dengue, Zika, chikungunya, and yellow fever account for about 17% of all infectious diseases globally, claiming more than 700,000 lives each year, and inflicting suffering on many more. The 2015 outbreak of Zika in Brazil was linked to an increase in the number of babies being born with microcephaly. 

Experiment with genetically modified mosquitos backfires in Brazil

Via brazzil.com, a September 21 report: Experiment with Genetically-Modified Mosquitoes Backfires in Brazil. Excerpt:

An attempt to contain the populations of the yellow fever mosquito Aedes aegypti in Brazil may have failed. It appears that gene mutations have been transferred to the local population. 

The British company Oxitec had released about 450,000 male mosquitoes every week in the city of Jacobina in the Bahia region with official permission over a period of 27 weeks. The experiment was designed to control the infectious diseases dengue, Zika and yellow fever. 

The gene modification called OX513A in the mosquitoes was designed in such a way that the first descendant generation of the mosquitoes, known as F1, would not reach the adult stage and thus not be able to reproduce. 

The hope of the Ministry of Health was to reduce mosquito populations by 90 percent. And this worked well during the field trial. About 18 months after the end of the experiment, the mosquito population returned to what it had been before. 

The gene modification of the released mosquitoes also produced a fluorescent protein that made it possible to distinguish the first F1 generation from other mosquitoes.  

Researchers at Yale University have examined the mosquitoes found in the region for their genetic alterations one year after the release, as well as 27 to 30 months after the release.  

They came to the conclusion that parts of the gene alteration had unexpectedly migrated into the target population of local mosquitoes. 

Gene Modification Passed On 

In the different samples, between 10 and 60 percent of the mosquitoes carried corresponding changes in the genome. The study was published in Nature: Scientific Reports on September 10.  

If the field trial had taken place as originally predicted, the gene modification would not have been allowed to migrate into the mosquito populations because the offspring of the mosquitoes originally released would not have been able to reproduce. 

However, it was already known from previous laboratory experiments that a small proportion of about three to four percent of OX513A descendants can reach adulthood; the scientists had assumed that those would be too weak to reproduce.  

The authors of the study found that the GM mosquitoes were equally suitable as carriers of infectious diseases as the mosquitos were before the experiment. 

Critics Take the Floor  

The Yale research team around Jeffrey Powell warns that the newly formed mosquito population could possibly be more robust than the mosquitoes were before.  

The authors conclude: “These results demonstrate the importance of having in place a genetic monitoring program during releases of transgenic organisms to detect unanticipated consequences”. 

Biologists critical of genetic engineering go one step further with their criticism, among them the Brazilian biologist José Maria Gusman Ferraz: “The release of the mosquitos was carried out hastily without any points having been clarified,” Ferraz told the newspaper Folha de S. Paulo.

ECDC rapid risk assessment: Autochthonous cases of dengue in Spain and France

ECDC has published Rapid risk assessment: Autochthonous cases of dengue in Spain and France. Excerpt from the executive summary:

On 16 September 2019, the Catalonian Public Health Agency confirmed an autochthonous case of dengue in a resident of Barcelonès county in Catalonia, Spain. The case had onset of symptoms on 6 September 2019, with no recent travel history outside of Spain. Dengue infection was confirmed by the Catalan reference laboratory for arboviruses and the Spanish national reference laboratory for arboviruses. Epidemiological investigations in Catalonia are ongoing, and further cases may be detected. According to national authorities, control measures are being implemented.  

On 20 September 2019, the regional public health agency of Provence-Alpes-Côte d’Azur region reported a locally acquired confirmed case of dengue in a resident of the city of Vallauris in the department of Alpes-Maritimes. The case had onset of symptoms on 30 August and did not report any recent travel history outside of mainland France. This case was laboratory-confirmed by the French National Reference Centre for Arboviruses (NRC, Marseille). Door-to-door active case finding was implemented around the home of the autochthonous case on 19 September. Four additional cases in the direct vicinity were identified. 

In addition, the regional public health agency of Auvergne-Rhône-Alpes reported a locally acquired probable dengue case in a resident of Caluire-et-Cuire − a suburban area of the city of Lyon − in the Rhône department. The case had onset of symptoms on 14 July 2019. For this case, NRC laboratory confirmation is still pending. The case did not report any recent travel outside of mainland France. 

To date, these three events should be considered as independent because epidemiological investigations could not identify any epidemiological links between them.

How mosquitos shaped humanity

The Tyee has published my review of Timothy C. Winegard's new book The Mosquito: A Human History of Our Deadliest Predator: How Mosquitos Shaped Humanity. Excerpt:

The mosquito, Timothy Winegard argues, has killed half of all humans who ever lived — 52 billion of us.  

Add all the other mammals and birds it preys upon, and it is clearly the planet’s apex predator. After millions of years in that role, however, the mosquito could be overthrown by its human victims’ ingenuity. 

Winegard’s research makes this an important book for anyone concerned with mosquito-borne diseases. As his subtitle suggests, he focuses on how mosquitos have shaped human history. And they have even shaped us genetically. Humans evolved in an Africa where mosquitos had prospered for millions of years. They preyed on our ancestral species, and by the time modern humans emerged we had even evolved sickle-cell anemia as a defensive measure against malaria.  

Modern humans who left Africa took malaria and other mosquito-borne diseases with them, infecting the mosquito populations they encountered. Migration and settlement must have come at a terrible price in deaths and sickness. The survivors, after repeated infections, might become “seasoned” — able to recover from malaria relatively easily. But if they moved into a new region, an unfamiliar strain of malaria might still finish them off.

Cross-protection of dengue virus infection against congenital Zika syndrome, northeastern Brazil

Via Emerging Infectious Diseases: Cross-Protection of Dengue Virus Infection against Congenital Zika Syndrome, Northeastern Brazil. The abstract:

The Zika virus outbreak in Latin America resulted in congenital malformations, called congenital Zika syndrome (CZS). For unknown reasons, CZS incidence was highest in northeastern Brazil; one potential explanation is that dengue virus (DENV)–mediated immune enhancement may promote CZS development. 

In contrast, our analyses of historical DENV genomic data refuted the hypothesis that unique genome signatures for northeastern Brazil explain the uneven dispersion of CZS cases. To confirm our findings, we performed serotype-specific DENV neutralization tests in a case–control framework in northeastern Brazil among 29 Zika virus–seropositive mothers of neonates with CZS and 108 Zika virus–seropositive control mothers. Neutralization titers did not differ significantly between groups. In contrast, DENV seroprevalence and median number of neutralized serotypes were significantly lower among the mothers of neonates with CZS. 

Supported by model analyses, our results suggest that multitypic DENV infection may protect from, rather than enhance, development of CZS.

ECDC: CDTR, 11-17 August, week 33

ECDC has published Communicable disease threats report, 11-17 August 2019, week 33. The summary:

This issue covers the period from 11 to 17 August 2019 and includes updates on Ebola virus disease in the Democratic Republic of the Congo, chikungunya virus disease and dengue, monitoring environmental sustainability of Vibrio growth in the Baltic Sea, the mass gathering of the Hajj in Saudi Arabia, tularaemia in Sweden and West Nile virus infection.

PAHO: Dengue in the Americas

Via ReliefWeb, PAHO has published Epidemiological Update - Dengue - 9 August 2019. The situation summary:

In the Region of the Americas, between epidemiological week (EW) 1 and EW 30 of 2019, a total of 2,029,342 cases of dengue (207.9 cases per 100,000 population) have been reported, including 723 deaths. Of the total cases, 846,342 (42%) were laboratory-confirmed and 12,268 (0.6%) were classified as severe dengue. The reported case-fatality rate was 0.04%.  

The number of cases reported as of EW 30 (2,029,342) is higher than the annual totals reported during the most recent two years (2017-2018) and, to date, is lower than the annual totals reported during the 2015-2016 epidemic cycle (Figure 1).  

In 2019, Guatemala, Honduras, and Nicaragua have declared epidemiological alerts at the national level as public health measures for the prevention and control of dengue and other arboviruses. This measure allows for a more rapid response in order to help mitigate the effects of the continued increase in cases, particularly considering the rainy season, which typically lasts until October or November in these countries.

Dengue in Central American and the Caribbean

Via ReliefWeb, OCHA has published Latin America & the Caribbean: Weekly Situation Update (29 July-5 August 2019) - As of 5 August 2019. Excerpt:

CENTRAL AMERICA: DENGUE OUTBREAKS 

KEY FIGURES 

42.3K CASES OF DENGUE IN HONDURAS THROUGH EPIDEMIOLOGICAL WEEK 30 

608 NEW CASES OF DENGUE IN GUATEMALA EACH WEEK  

2.2K HOSPITALIZATIONS OVER DENGUE IN EL SALVADOR  

441 CASES OF DENGUE FOR EVERY 100,000 INHABITANTS IN NICARAGUA, THE HIGHEST RATE IN CENTRAL AMERICA 

HONDURAS 

On orders of the Ministry of Health, all 1,606 health centers in Honduras are to stay open until 7:00pm, which should allow them to take the burden off public hospitals, nearly all of which are currently overrun with dengue cases.  

The Ministry also reports that they will open 15 Dengue Attention Clinics (CAD) within existing facilities, with two in the national capital of Tegucigalpa and two more in San Pedro Sula in northern Honduras. The CAD facilities will hire additional personnel to provide 24 hour service. 

Through epidemiological week (EW) 30, Honduras has accumulated 42,346 cases, with 9,793 cases of severe dengue and 156 total deaths. 

GUATEMALA 

Guatemala’s Ministry of Health formally declared a red epidemiological alert for dengue, allowing public health services to maintain permanent services for registration, notification, surveillance, weekly trend analysis and prevention campaigns until further notice. 

Health officials in Guatemala are concerned that water collection in drought-affected areas may become mosquito breeding sites 

According to the Ministry’s bulletin for epidemiological week 27, Guatemala is witnessing as many as 608 new cases each week. The Ministry’s head of epidemiology warns that the total number of cases may soon surpass 9,000, especially with Guatemala’s ongoing rainy season potentially leading to more disease-carrying mosquitos. 

EL SALVADOR  

Through 27 July, El Salvador has seen 10,316 suspected cases of dengue, 2,241 hospitalizations and 10 deaths. Although El Salvador’s health system has yet to declare any alert, they are coordinating with Civil Protection. 

PAHO/WHO is providing technical support for the Ministry of Health and supporting with virology diagnostic supplies for dengue, chikungunya and Zika, patient management guidelines and epidemiological analysis. Oxfam is supporting municipal authorities with fumigation campaigns and WASH supplies in schools. Save the Children is supporting 11 municipalities with existing Zika programs. 

NICARAGUA 

According to the Ministry of Health, there are 55,289 suspected cases of dengue in Nicaragua through epidemiological week (EW) 30, a 138 per cent increase from EW 30 2018. The Ministry declared an alert on 30 July that will scale up prevention and attention actions until November.  

According to PAHO/WHO, Nicaragua trails only Brazil in incidence of dengue cases, with 441 cases for every 100,000 inhabitants. Despite the high frequency of cases, Nicaragua has the lowest mortality rate in the region, with only eight deaths.

Philippines declares a national dengue epidemic

Via The New York Times: Philippines Declares a National Dengue Epidemic. Excerpt:

MANILA — The Philippines declared a national dengue epidemic on Tuesday, saying that the mosquito-borne disease had killed at least 622 people in the country so far this year. 

More than 146,000 dengue cases were reported in the first seven months of the year, almost twice as many as in the same period last year, according to the country’s health department. 

“This is really staggering,” said Francisco Duque, the health secretary. He said the declaration of an epidemic was needed so that local governments in badly hit places could use “quick response funds” to fight the disease. 

Officials said the Western Visayas region of the Philippines had the most cases, at more than 23,000, followed by the suburbs south of Manila, the capital, which had more than 16,500 cases. Parts of the southern island of Mindanao also reported a high number of infections.

The Philippine government has struggled to address dengue since December 2017, when it stopped using a vaccine called Dengvaxia that was found to pose health risks to people who had not previously had the disease. 

Two years earlier, the Philippines had become the first country in Asia to approve the commercial sale of Dengvaxia, in what was then considered a medical breakthrough. The drug was distributed to almost a million children through a school immunization program, with the government arguing that it had been approved for use by the World Health Organization. (The group later said that it had not given a “blanket recommendation” to use the drug.)  

But the program was halted after the French pharmaceutical giant Sanofi, which developed Dengvaxia, announced that in rare cases, vaccinating people with no prior history of dengue infection could lead them to develop a more severe form of the disease.  

With the discontinuation of Dengvaxia, the Philippines has been left with little means to combat the spread of dengue, Mr. Duque said. He asked the public to help by destroying mosquito breeding sites. 

About 400 million people around the globe are infected by dengue every year, making it the most widespread mosquito-borne disease. The illness can be excruciating, with symptoms including high fevers, headaches, muscle and joint pains, and lingering weakness.