H5N1

Reduced dengue incidence following deployments of Wolbachia-infected Aedes aegpti in Yogyakarta, Indonesia

After endless COVID-19 coverage, it's a pleasure to post this article by members of the World Mosquito Program: Reduced dengue incidence following deployments of Wolbachia-infected Aedes aegpti in Yogyakarta, Indonesia. The abstract:

Background: Ae. aegypti mosquitoes stably transfected with the intracellular bacterium Wolbachia pipientis (wMel strain) have been deployed for biocontrol of dengue and related arboviral diseases in multiple countries. Field releases in northern Australia have previously demonstrated near elimination of local dengue transmission from Wolbachia-treated communities, and pilot studies in Indonesia have demonstrated the feasibility and acceptability of the method. We conducted a quasi-experimental trial to evaluate the impact of scaled Wolbachia releases on dengue incidence in an endemic setting in Indonesia. 

Methods: In Yogyakarta City, Indonesia, following extensive community engagement, wMel Wolbachia-carrying mosquitoes were released every two weeks for 13–15 rounds over seven months in 2016–17, in a contiguous 5 km2 area (population 65,000). A 3 km2 area (population 34,000) on the opposite side of the city was selected a priori as an untreated control area. Passive surveillance data on notified hospitalised dengue patients was used to evaluate the epidemiological impact of Wolbachia deployments, using controlled interrupted time-series analysis. 

Results: Rapid and sustained introgression of wMel Wolbachia into local Ae. aegypti populations was achieved. Thirty-four dengue cases were notified from the intervention area and 53 from the control area (incidence 26 vs 79 per 100,000 person-years) during 24 months following Wolbachia deployment. This corresponded in the regression model to a 73% reduction in dengue incidence (95% confidence interval 49%,86%) associated with the Wolbachia intervention. Exploratory analysis including 6 months additional post-intervention observations showed a small strengthening of this effect (30 vs 115 per 100,000 person-years; 76% reduction in incidence, 95%CI 60%,86%). 

Conclusions: We demonstrate a significant reduction in dengue incidence following successful introgression of Wolbachia into local Ae. aegypti populations in an endemic setting in Indonesia. These findings are consistent with previous field trials in northern Australia, and support the effectiveness of this novel approach for dengue control.

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.

PAHO issues $3.5 million donor appeal for humanitarian health response in the Bahamas

A news release from PAHO: PAHO issues $3.5 million donor appeal for humanitarian health response in the Bahamas. Once again, the first response to a public health disaster is to beg for money:

Nassau, Bahamas, Sept. 8, 2019 (PAHO)—The Pan American Health Organization (PAHO) is requesting an initial US $3.5 million from donors to cover short-term health care and other needs for the population in the Bahamas affected by Hurricane Dorian.

The devastating category 5 storm made landfall exactly one week ago in northwest Bahamas, and severely affected the health sector, with significant destruction of equipment and medical supplies and electrical and water supplies in Abaco and Grand Bahama. Some 73,000 persons were affected by the storm, and there are hundreds of people in shelters in the disaster zone. While 43 deaths have been officially reported thus far, mass casualty numbers are expected to rise significantly as more areas become accessible and search and rescue operations continue.   

Dr. Ciro Ugarte, PAHO’s Director of Health Emergencies, said, “Our priority concerns are to restore access to essential health services and continued medical care delivery, to ensure water quality in affected communities and health facilities, and to restore proper hygiene and sanitation.” He said adequate waste management and control of disease-causing vectors such as mosquitoes is key, along with increasing epidemiological surveillance to support early detection and timely management of disease outbreaks. 

The $3.5 million being requested by PAHO is a preliminary estimate to cover short- term healthcare, water and sanitation, epidemiological surveillance and vector-control needs in the Bahamian Islands most affected by Hurricane Dorian for the next six months, Dr. Ugarte said, adding that needs will likely increase as damage assessments are completed. 

PAHO/WHO activated its emergency teams for surge capacity and had pre-deployed Rapid Response Team experts to the Bahamas before Hurricane Dorian struck to support health authorities and humanitarian response as needs were identified. So far, 14 PAHO experts are in the disaster zone to provide surge capacity in logistics, civil and military coordination, information management, epidemiological surveillance, communications, and coordination.

Dr. Ugarte said PAHO is acting quickly to support the Bahamas Ministry of Health in the response, setting up an Incident Management system and co-leading the health cluster with the national health authorities to coordinate health and humanitarian support to the affected population.

The funding requests includes $1.3 million to restore healthcare delivery in affected areas, $500,000 for surveillance to detect and manage disease outbreaks, $800,000 for safe access to water, emergency sanitation and control of disease vectors, and well as $671,000 to coordinate humanitarian assistance and manage information to address the most urgent humanitarian needs.

Bangladesh dengue cases reach nearly 25,000 as nationwide outbreak continues unabated

It's not just Honduras. Via Xinhua: Bangladesh dengue cases reach nearly 25,000 as nationwide outbreak continues unabated. 

DHAKA, Aug. 4 (Xinhua) -- Dengue cases in Bangladesh have surged to around 25,000 nationwide with 18 deaths so far this year, the Directorate General of Health Services (DGHS) said on Sunday.  

On Aug. 1-4, according to the figure reported by the DGHS under the Ministry of Health, 6,967 more dengue cases were recorded after more than 15,359 people were infected with the mosquito-borne disease in the last month, which were more than the total number of patients in any past year. 

According to the DGHS, the number of patients was 10,148 in the last year including 946 cases in July 2018 and 26 of them died.  

At least 75 people reportedly died of dengue this year till Sunday in the country. But the DGHS puts the figure at 18.  

"As of Aug. 4, 2019, a total of 24,804 cases of Dengue virus disease, including 18 deaths, have been reported in the country since Jan. 1," Ayesha Akhter, assistant director at the DGHS, told Xinhua. 

Meanwhile, she said a total of 1,870 fresh dengue cases were reported in the 24 hours till 8:00 a.m. local time Sunday, the highest number in a single day. 

Mirjadi Mehjabin, director of the government's Institute of Epidemiology, Disease Control and Research (IEDCR), said earlier that dengue virus is unlikely to abate soon as the Aedes mosquito, which is the carrier of the virus, continues to breed till September. 

She underscored the importance of detecting and destroying properly breeding grounds of the mosquito to rein in the fast outbreak of the disease. 

DGHS officials urged the authorities concerned to take prompt measures to destroy the mosquito breeding grounds to prevent the disease from turning into an epidemic. 

Many government agencies including the Dhaka Metropolitan Police (DMP) launched cleanliness campaigns in the capital city to control the dengue outbreak. 

According to a DMP statement, all offices of deputy commissioners of police, police stations, police camps, control rooms, messes and dining places for the policemen under the DMP were cleaned during a campaign Saturday as several policemen and their family members have also been victim of the dengue fever. 

At a hospital on Sunday in Dhaka, a senior police official's spouse reportedly died of dengue fever. 

By region, according to officials, Dhaka and its neighboring districts are still more vulnerable to the risk of mosquito-borne diseases.  

Most Dhaka hospitals and clinics are crammed with dengue patients. On Sunday one of  Dhaka's largest public hospitals - Shaheed Suhrawardy Medical College Hospital - was seen flooded by hundreds of patients suffering from dengue fever, which is transmitted by several species of mosquito within the genus Aedes. 

The first case of mosquito-borne viral infection was reported in Bangladesh in 2000, and some 100 people died from the disease in 2000-2003.

Honduras hospitals 'overrun' by dengue fever

Via Global Health NOW: Honduras Hospitals “Overrun” by Dengue Fever. Excerpt and then a comment:

Dengue fever has “overrun” 26 of Honduras’s 32 public hospitals. The virus has afflicted 28,000 and killed 54 people—mostly children—so far this year, reports AFP.   

A hospital in La Paz resorted to putting patients up in its chapel, and still has beds lining the corridors. “In 20 years working here, I've never seen this,” said hospital spokesman Marco Antonio Rodas.   

Officials called a national emergency, and launched a sweeping fumigation campaign to destroy Aedes aegyptii mosquito breeding grounds.  

The country is conducting a major mosquito-control campaign today, and the death toll is now 59. One site reports the hospital system has collapsed under the impact.

Dengue 3 outbreak, Palau, December 2018 – June 2019

Via ReliefWeb, a report from the government of Palau: Dengue 3 Outbreak, Palau, December 2018 – June 2019. The overview:

On Friday, December 7, 2018, the Palau Ministry of Health alerted the public of an outbreak of dengue fever following the first ever laboratory confirmation of two cases with dengue serotype 3. This poses a significant concern for public health as the whole population is potentially vulnerable to infection.  

In response to the outbreak, the Ministry of Health activated its emergency response team on December 7, 2018. The team has been tasked with raising community awareness of the outbreak and dengue prevention measures, conducting disease surveillance and reporting, strengthening mosquito control measures, and ensuring adequate resources are available to combat the outbreak. 

Between June 10 June 16, 2019, there were 15 new cases reported. This brings the total from December 1, 2018 to June 9, 2019 to 250 cases. 

There have been no reported deaths attributed to dengue infection during this outbreak.

Chikungunya in DR Congo: Concern over lack of response to the epidemic

Via mediacongo.net, a reminder that Ebola isn't the DR Congo's only health problem: "Chikungunya": Concern over lack of response to the epidemic. The Google translation:

The disease is currently rife in Kinshasa and Kongo Central, two provinces of the Democratic Republic of Congo. Chikungunya, this epidemic caused by the mosquito Aedes, was the subject of a scientific morning to the attention of journalists, Tuesday May 14, 2019, veterinary clinics of the capital.   

According to prof. Justin Masumu, Director of Studies of the Interdisciplinary Center for Health Risk Management (CIGRS), this meeting was held for all together, journalists and scientists to reflect on the Chikungunya epidemic. Since 2018, this epidemic has started in the DRC in the health zone of Mount Ngafula I and II. Currently, it is located in Matadi through several cities of central Kongo. 

How to fight? 

Neither vaccine nor any product can kill the Chikungunya virus. This is why management is symptomatic. Teacher Justin Masumu informs, it is necessary to administer to the patient nonsteroidal anti-inflammatory drugs, to avoid hemorrhages.  

When the surveillance samples arrive at the National Institute for Biomedical Research (INRB) however, the test is performed free of charge. If this disease was under surveillance at the medical center level, all suspected cases should be transferred to the INRB.  

To fight against Chikungunya, you have to rely on the way in which transmission is done. It is by the mosquito Aedes and can multiply even in homes through flower pots, boxes of sardines, which are places where these mosquitoes can multiply. Reason why the fight is anti vector. 

"We must use all possible means to prevent the multiplication of mosquitoes," he said. There is also the problem of the reservoir, since it is many more monkeys and birds that are vectors. Again, there is the possibility to monitor all these animals. He suggested that action be taken on the ecological side by veterinarians for the surveillance of all these reservoirs. 

Testimonials from the survivors 

A dozen survivors of Chikungunya testified during this meeting. Mrs. Regine Nsuka, forty or so years old, living in Mont Ngafula, says: "On December 27, 2018, I felt bad when I got home from work. I immediately took two tablets of Amidol. My head hurt, my joints hurt, and I could not get up. I did not have an appetite either and could not eat for seven days. I was subjected to Amidol and Fort muscle by my husband who is a doctor. It was seven days later, I recovered. However, there are times when I feel cramps in my arms."  

Mrs. Mélanie Kapinga, in her fifties, living in Limere, Kingabwa, explains: "In mid-March, I returned from the place where I work with aches, fever and the situation gradually worsened. I was worried because I did not have neck pain, which is the case every time I have a malaria problem. Once spread out on the bed, I could not get up. I decided to go to the hospital from 5pm when it was gone. There I told the doctor that I did not think I would get up the next day. He's the one who prescribed me products that I do not know the name. I recovered three weeks later. Until now, I have from time to time pain in the joints. It's a very bad disease."

WHO: Chikungunya – The Congo

WHO has published Chikungunya – Congo (The). This is the neighbour of the Democratic Republic of the Congo. Excerpt:

On 9 February 2019, the government of Congo officially declared an outbreak of chikungunya virus disease. 

The outbreak was detected following an increase in the number of patients presenting to several health facilities with signs and symptoms of sudden onset of fever, joint pain and muscle pain and a subsequent laboratory confirmation of 12 samples in the National Institute of Biomedical Research (INRB) in Kinshasa. The first suspected case was a symptomatic 49-year-old woman who presented on 7 January 2019 to a health facility in Diosso town, 25 kilometres north of Pointe-Noire. Samples taken during a joint investigation of the Ministry of Health (MoH) and WHO tested positive to chikungunya on polymerase chain reaction (PCR) at INRB in Kinsasha. 

From 1 January to 14 April 2019, a total of 6,149 suspected cases of chikungunya have been reported in the country with approximately 54% of reported cases being female. One hundred and seventy-three blood samples have been collected with 61 (35.3%) testing positive by PCR at INRB. 

However, the scale of this outbreak has likely been underestimated given the limited detection capacity of the surveillance system in the country. Several mosquito breeding sites in affected areas and inadequate vector control mechanisms also represent major contributing factors for the outbreak. 

The Ministry of Health has reported that the outbreak has spread to eight of twelve health departments in the country (Kouilou, Bouenza, Pointe Noire, Plateaux, Pool, Niari, Lékoumou and Brazzaville). Since the report of the first case on 7 January 2019, 47% of all cases have been reported from Kouilou Department. No deaths have been reported. This is the second outbreak reported in Congo since 2011 and no seasonal pattern has previously been observed.

WHO: Yellow fever – Nigeria

WHO has published Yellow fever – Nigeria.

On 22 November 2018, the World Health Organization was informed of a cluster of suspected Yellow fever (YF) cases and deaths in Edo State, Nigeria. Edo State is located less than 400km from Lagos on a dense population movement axis between Lagos and South-Eastern Nigeria. Edo State is also a known endemic area for Lassa fever – which was initially suspected as causing the outbreak. 

From 22 September through 31 December 2018, a total of 146 suspected, 42 presumptive positive, and 32 confirmed cases, including 26 deaths (presumptive case fatality rate: 18%), have been reported across 15 of 18 Local Government Areas (LGAs) in Edo State (figure 1). 

Blood specimens were obtained from 122 cases and sent for laboratory diagnosis; 42 (34%) samples were presumptive positive in-country based on IgM serology and sent to the regional reference laboratory, Institut Pasteur de Dakar (IPD), for confirmation. Thirty-two (76%) were confirmed by plaque reduction neutralization test (PRNT) or real-time polymerase chain reaction (RT-PCR). Males represent the majority of cases (108 of 146, 74%), and the most affected age group is 10–19 years with 48 cases (33%), followed by the age group 20–29 with 36 cases (25%). Initially, the affected LGAs were rural but since the end of November 2018, suspected cases have been reported from three urban LGAs. There has also been a report of two presumptive positive and one confirmed case in Oredo LGA, which includes the densely populated state capital Benin City, of about 1.5 million inhabitants.  

At the time of the outbreak, population immunity in Edo State was very low, (based solely on routine immunisation administrative data, with vaccine coverage estimated at less than 50% in 2018). Edo State has just concluded a seven-day YF Reactive Vaccination Campaign implementation in 13 LGAs to rapidly boost population immunity and interrupt YF transmission. As of 31 December 2018, 1.47 million people have been vaccinated.  

Entomological studies have revealed elevated indices of competent vectors, including Aedes aegypti, the mosquito species responsible for rapid amplification of arboviral disease in urban environments. Land-use practices, namely cultivation close to dwellings, may further exacerbate the spread of YF disease in this setting. 

Since September 2017, when the Nigeria Centre for Disease Control (NCDC) informed WHO of a confirmed case of YF in Kwara State, Nigeria has been responding to successive YF outbreaks. The country officially notified WHO (via the International Health Regulations, 2005) on 15 September 2017. Since then, and as of 30 December 2018, 237 specimens tested IgM positive in-country. Eighty-two cases (including 13 deaths) were confirmed by IPD; these cases were reported from 27 LGAs in 14 States and have resulted in response campaigns in selected LGAs in six states.  

The current outbreak of YF in Edo State in Nigeria is unusual in scale and severity, and the number of cases in time and place is very high in the context of the current national outbreak. The seasonal timing of the outbreak, in a period where many travellers enter the state from other states and countries for the holidays in December–January, adds to the risk for potential spread.