LUANDA - Angola declared the end of the world's worst yellow fever epidemic in a generation on Friday after a UN-backed vaccination campaign of 25 million people that resulted in no new cases in six months.
The outbreak began a year ago in a slum in the capital, Luanda, before spreading throughout Angola, a war-scarred southeast African nation, and into neighbouring Democratic Republic of Congo. In all, more than 400 people died.
More than 15 million Angolans and 10 million Congolese were vaccinated under a campaign coordinated by the World Health Organization (WHO).
In a statement entitled "The end of the epidemic of Yellow Fever in Angola", the health ministry in Luanda said the vaccination campaign had stopped the spread of the disease.
The WHO said in September the epidemic was under control but that it was too early to say it had been completely stamped out, with up to 6,000 suspected cases of the mosquito-borne disease.
The vaccination campaigns depleted the global stockpile of 6 million doses twice this year, forcing doctors to switch to administering one-fifth of the normal dose, a tactic that the WHO says gives at least temporary protection.
The risk of such outbreaks globally has risen in recent years due to urbanization and the increasing mobility of the population. It was particularly acute this year because of the El Nino weather phenomenon which multiplied mosquito numbers.
Yellow fever is transmitted by the same mosquitoes that spread the Zika and dengue viruses. The "yellow" in the name refers to the jaundice that affects some patients.
A child being vaccinated against yellow fever in the Democratic Republic of Congo in July.CreditKenny Katombe/Reuters
The yellow fever outbreak in Africa this year came closer to being a disaster than is widely recognized, public health experts recently disclosed. The epidemic also revealed glaring weaknesses in the emergency vaccine supply pipeline.
The first deaths in Angola were misdiagnosed as food poisoning; the global emergency vaccine stockpile was depleted before even one city was fully protected; and diagnostic laboratories were so far away that it was months before the scope of the outbreak was clear and a worldwide alarm was raised.
Ultimately, the yellow fever outbreak was halted only by a huge vaccination campaign that stretched supplies by diluting doses, and even that succeeded only because some unusual donors stepped in.
Brazil contributed 18 million doses of yellow fever vaccine — three times the amount in the emergency stockpile — to contain the African outbreak. Even South Sudan, one of the world’s poorest nations, gave up 400,000 doses intended for its children.
The outbreak, which began last December and appeared to be over as of September, went largely unnoticed because attention was focused on the Zika epidemic. Some aspects were truly frightening, experts said at the annual conference of the American Society of Tropical Medicine and Hygiene in Atlanta in mid-November.
For the first time, the virus reached Asia — a continent with no yellow fever immunity. Ultimately, however, there were only 11 cases in China, all in returnees who had been working in Africa.
“It did not get a foothold in Asia, but if it did, it would be a real nightmare,” said Dr. Axelle Ronsse, an emergency medical coordinator for Doctors Without Borders, which led the fight against yellow fever in the Democratic Republic of Congo.
After the first case was detected in Beijing, John P. Woodall, a co-founder of the disease-alert service ProMed-mail, warned that spread in Asia “could make the Ebola and Zika epidemics look like picnics in the park!”
More than 100,000 Chinese work in Africa and many, Dr. Woodall noted, come from tropical southern China where Aedes mosquitoes already spread dengue and could spread yellow fever.
Kinshasa, Congo’s capital, narrowly missed having a runaway outbreak. There were only 16 cases far from the crowded city center.
Just 50 cases, Dr. Ronsse said, would have overwhelmed her mosquito-control teams, which sprayed 325 acres of the city.
Although there were fewer than 1,000 laboratory-confirmed cases in the outbreak over all, there were more than 6,000 suspected cases and undoubtedly many more unreported.
Only about 15 percent of cases get the characteristic yellow eyes, dark urine and abdominal pain, but half of them die.
Yellow fever was one of the great scourges of the 18th and 19th centuries. Imported to the Americas from Africa with the slave trade, the mosquito-borne virus regularly killed hundreds of thousands in Latin America and the Caribbean.
From 1702 to 1822, outbreaks emptied out New York City several times as residents, banks and government offices moved north to Greenwich Village or farther in search of safety. In 1793, the fever killed a tenth of the population of Philadelphia, which was then the nation’s capital.
Photo
Residents of the Kisenso district of Kinshasa lined up to receive the yellow fever vaccine.CreditJerome Delay/Associated Press
Since a vaccine was invented in the 1930s, it has been held in check, circulating in monkeys in Africa and the Amazon jungle. The virus regularly starts small outbreaks in remote villages, but it can cause explosive urban outbreaks when it is transmitted from forest mosquitoes to Aedes aegypti, which prefers to live among humans.
Aedes aegypti is called the yellow fever mosquito, but it also transmits Zika, dengue and other pathogens.
In December 2015, four Eritrean workers who frequented the market in Viana, a suburb of Luanda, died, as did the owner of a restaurant where they ate. Food poisoning was suspected at first.
It was not until January, after blood samples reached the Pasteur Institute in Senegal, that the fever was diagnosed. By then it was spreading fast within Luanda, a metropolitan area of almost seven million.
By February, 12 Angolan provinces were affected. Why the disease never moved south into Namibia or east into Zambia is unclear. The borders are sparsely populated, two years of drought lowered mosquito populations, and those countries do some routine vaccination.
The virus did move north into Congo, which has two port cities, Boma and Matadi, on the border with Angola. Kinshasa, a city of 10 million, is just up the Congo River and across from Brazzaville, where two million more live.
A huge population was suddenly at risk, but the emergency vaccine stockpile, administered by a committee in Geneva, then held only six million doses.
The vaccine is grown in chicken eggs for as little as $1 a dose, said Dr. Thomas P. Monath, a vaccine expert formerly with the Centers for Disease Control and Prevention.
But because profits are low, many pharmaceutical companies dropped it. In 1970, 14 private or national vaccine factories made yellow fever vaccine; now only six do, and only four sell it to the World Health Organization. The manufacturers were asked to increase production, and other countries were asked to divert their supplies.
The outbreak turned into a race between the vaccine and the mosquitoes.
The first six million doses reached Luanda by late February, and officials in Angola requested four million more. Those did not all arrive until late May.
Then Congo urgently asked for two million doses, and Uganda, which had a brief, unrelated outbreak, requested one million. With panic spreading, it was reported that one million doses had been stolen, and that forged vaccination certificates were circulating.
On April 4, the situation looked so serious that the W.H.O. director-general, Dr. Margaret Chan, visited Luanda to draw attention to the crisis. On May 19, an expert advisory committee debated declaring a global emergency like the one it had declared for Zika in February. The committee decided to hold off because the outbreak appeared to be slowing.
Then Peru reported a big yellow fever outbreak, raising worry again; but it was brought under control without outside help.
Ultimately — and luckily — it was the mosquitoes that stumbled.
Doctors Without Borders vaccinated residents of Matadi, the Congo border city. In Kinshasa, it suppressed each of the 16 known cases by spraying every nearby house with three types of pesticide: spray on indoor walls, fog outdoors, plus larvide in standing water.
By October, more than 31 million people were vaccinated — but only by diluting each dose by five to one.
“The end of the story was successful,” Dr. Sylvie Briand of the W.H.O.’s outbreaks and emergencies branch, adding, with understatement, “but it was really a logistical challenge.”
If an outbreak had started in China, the crisis might have been much greater.
Dr. Monath calculated that 160 million doses would be needed to contain it — and only if, diluted tenfold, they still worked. At full capacity, the world’s vaccine factories produce half that many in a year.
The Gavi Board also responded to the growing number of disease outbreaks in Gavi-supported countries, such as the recent yellow fever epidemic in central Africa, by approving a new approach to Vaccine Alliance support for emergency stockpiles of meningitis, cholera and yellow fever vaccines. For diseases with limited vaccine supply, such stockpiles facilitate rapid access to vaccines during outbreaks.
Under the new approach, Gavi will make long-term funding commitments that allow our partners to plan for the future and also increase the security of supply. All Gavi-supported countries, regardless of their transition phase, will be able to access full vaccine and operational cost support. Other countries will be able to draw on emergency vaccine stockpiles but will be expected to reimburse the costs when the emergency is over.
“Emergency stockpiles can play an essential role both as part of a comprehensive disease control strategy and in maintaining global health security, but they are not a silver bullet,” said Dr Berkley. “They should be integrated into a wider strategy that builds better public health systems and improves childhood immunisation through stronger routine immunisation and pre-emptive vaccination campaigns.”
Gavi will also strengthen its engagement in support of yellow fever activities with additional funding of up to US$ 150 million for the period 2016-2020. Since 2000, Gavi has invested more than US$ 300 million in routine immunisation with yellow fever vaccines in high-risk countries, mass preventive campaigns and emergency stockpiling.
Having the right grades and the passion to have a life at the sea will not get you a career in the merchant navy. In order to join a merchant navy course, you must have the physical fitness and medical requirements that are necessary to have a career on ships.
The candidate must be in good mental and physical health and free from any kind of bodily defect to interfere with the efficient performance required at the sea. Read on to find out if you are physically fit to join the merchant navy.
1. Constitution
There should be no evidence of weak constitution by way of imperfect development of muscles or serious malformation. Weight below 42 kg and height below 150 cm will be rejected. The chest should be well developed with a minimum range of expansion of 5 cm.
2. Skeletal System
There should be no disease or impairment of functions of bones or joints, contracture or of deformity of chest or any joint, abnormal curvature of spine, deformity of feet like bow legs, knock knees, flat feet, deformity of upper limbs, malformation of the head, deformity from fractures or depression of the skull, fractures (healed) with a pin inside will be a disqualification.
3. Ear, nose and throat
There should be no impaired hearing, discharge or disease in either ear, unhealed perforation of tympanic membrane or signs of acute or chronic supperative otitis media or evidence of radical mastoid operation, evidence of disease of the bones and cartilage of the nose, nasal polypus or disease of nasopharynx or accessory sinuses. Loss or decay of teeth to such an extent as to interfere with efficient mastication. No disease of the throat, palate, tonsils or gums or any disease or injury affecting the normal function of either temporo mandibular joint. Individuals with severe pyorrhoea are to be rejected.
4. Speech
There should be no impediment of speech (e.g. stammering)
5. Lymphatic System
There should be no enlarged glands, tubercular or due to other diseases in the neck or other parts of the body. Thyroid gland should be normal.
6. Cardiovascular System
There should be no sign of functional or valvular or other disease of the heart and blood vessels. Electrocardiogram should be within normal limits. Systolic blood pressure should not exceed 150mm of Hg nor Diastolic above 90 mm of Hg.
7. Respiratory System
There should be no evidence of chronic or respiratory tract disease, pulmonary tuberculosis or previous history of this disease or any chronic disease of the lungs. X-ray of chest should be normal.
8. Digestive System
There should be no evidence of any disease of the digestive system and that liver and spleen should not be palpable and there should be no abdominal tenderness on palpation.
9. Genitourinary System
There should be no palpable and enlarged kidneys. There should not be any disease of kidneys. Cases showing alburminuria, glycosurea or blood (RBC) in urine will be rejected. There should be no hernia or tendency thereto. Those who have been operated for hernia may be declared fit provided:
(a) One year has elapsed after the operation. Documentary proof to be produced by the candidate.
(b) General tone of abdominal muscles should be good and
(c) There has been no recurrence of hernia or complications with the operation. There should be no hydrocele, vericocele, spermatocele or any other defect of genital organs, no fistula and/or anal fissure or evidence of hemorrhoids (Piles), rectal polyps. There should be no active latent or congenital venereal diseases, undescended intra abdominal testicle on one side unassociated with hernia, provided the other testicle is normal and that there is no physical or psychological effect due to undescended testicle will be accepted. Undescended testicle is retained in inguinal canal or at the extra abdominal ring will be rejected.
10. Skin
There should be no skin disease unless temporary or trival. Scars which by their extent or position are likely to cause disability or marked disfigurement are a cause for rejection.
11. Nervous System
There should be no history or evidence of mental disease of the candidate or in his family. Candidates having history of fits in continence or urine or enuresis will not be accepted. Mental or nervous irritability, abnormality of gait, defective functions of cranial nerves, inco-ordination, motor or sensory defaults will be rejected.
12. Eye Sight
There should not be any degree of squint or any morbid condition of eyes or of the eyelids that is liable to aggravate or recur, pressure of trachome and iris complication sequela. Candidates must possess good binocular vision (fusion faculty and full field of vision in both eyes). Movement of the eyeballs must be full in all directions and the pupils should react normally to light and accommodation.
The vision should be 6/6 (normal) in each eye separately. Defective colour vision tested byIshihara Colour Blindness Test is a disqualification.
13. Any other defect which in the opinion of the medical board will interfere with the individual’s efficiency as an officer of the merchant navy.
As cases of Zika virus increase there is considerable investigation and research into the virus. One area being looked at for clues is yellow fever virus. A second area involves the use of mouse models.
Zika virus is a member of the Flaviviridae virus family. In one in four people the disease causes a mild illness known as Zika fever, for up to seven days. The symptoms include fever, rashes, joint pain and conjunctivitis. The biggest risks are infected women and babies born with abnormally small heads and brain defects, a condition called microcephaly.
Yellow fever and Zika viruses have a common characteristic in how they can circumvent an insect’s immune response. This is due to the viruses manufacturing proteins that can suppress the immune response in the host. A similar response occurs in people, when we become infected.
For this reason, researchers have been studying mosquitoes and viral infections. This is based on using gene drive, a method targeting specific genes. The idea is to tip the battle at the genetic level in favor of the mosquito. This tranche of research could eventually lead to a human vaccine.
A second wave of research, also from Texas A&M University, College Station, is finding a means to make an infective mosquito undergo altered behavior so that it will not seek out humans to infect.
The research has been published in the journal Proceedings of the National Academy of Sciences. The paper is titled “Yellow fever virus capsid protein is a potent suppressor of RNA silencing that binds double-stranded RNA.”
In a second wave of research, a different group of researchers are seeing whether mice with healthy immune systems could provide new insights into Zika virus pathology and treatment. This is not straightforward due to the changes that animals undergo when they are infected. Mice, however, can, under certain conditions, be used as ideal models for Zika virus research.
The reason for focusing on mice is because studies have indicated that young mice with specific immune system defects are susceptible to Zika infection. By rearing mice (coded C57BL/6) with functioning immune systems that can be successfully infected with Zika, more detailed studies can be made and to provide the basis for testing treatments.
The second research study has been published in the journal PLOS Pathogens. The paper is headed “Zika (PRVABC59) Infection Is Associated with T cell Infiltration and Neurodegeneration in CNS of Immunocompetent Neonatal C57Bl/6 Mice.”
Insect repellent, screens on windows, wearing long sleeves -- there is a limit to the precautions that we can take to protect ourselves from viruses that are spread by mosquitoes.
Even by taking all of the above steps, there is no way to have guaranteed protection from mosquito bites.
But, there is one idea that would put an end to all other methods of mosquito repellents.... what if there were no mosquitoes?
That is the idea behind the work of the company Oxitec. They have engineered a mosquito that leads to a decrease in the Aedes aegypti mosquito population. Here is how it works. The company has created a strain of mosquito that is "self limiting" meaning that they have a "death gene" added to their genome that kills their offspring. This strain of mosquitoes is called OX513A, but, they are referred to by the company as 'friendly Aedes.'
The process starts with the hatching of the OX513A mosquitoes. Then, the males and females are separated from each other. This is easy because males and females are different sizes. Also, the male strain is labeled with a red fluorescent marker, which makes it even easier to tell the difference, in case the size was unclear. After separation, the females are destroyed. Because male mosquitoes do not bite or spread disease, their release will not exacerbate disease spread. Those same males, upon release, mate with wild females. When the offspring of those matings hatch, they die.
If enough of these males are released, the total population of mosquitoes will decrease, and eventually become too low to transmit disease.
Aedes aegypti spread Zika, Dengue fever, yellow fever, and chikungunya virus. One thing that these four infectious diseases have in common is a lack of treatment. If you get them, you wait it out and hope for the best. And, although there is an incredibly effective vaccine for yellow fever, it is widely under produced. So, avoiding mosquito bites is really the only defense against these diseases.
These mosquitoes have been released in trials in Brazil, Panama (for yellow fever and Dengue) and the Cayman Islands (for Zika.) All of the trials resulted in a 90% reduction of the wild mosquito population. In Brazil, a trial was done in a town of 5,600 people that saw 133 cases of Dengue fever before the trial. After the trial - there was only one case. (1)
The mosquitoes are expensive and many of them need to be released to see an effect. However, the difference between spending money on the 'friendly Aedes' versus sprays and larvicides is that the mosquitoes actually work.
However, people are cautious to sign up for releasing genetically modified organisms into their community. As more and more people are affected by vector borne illnesses, we will see which is more important - fear of science or infectious disease?
The Nigerian Centre for Disease Control (NCDC) has said that Zika Virus is spreading in Nigeria as a result of environmental conditions and other related issues.
The centre stated this in a report released to the media on Monday.
"The current epidemiology of Zika in Nigeria has not been well-documented or understood due to paucity of recent data", the report stated.
"The virus shares a similar vector; the Aedes (Steogmyia) mosquitoes, also responsible for other flavivirus infections recorded in Nigeria such as such as yellow fever.
"Consequently, environmental and human behavioural risk factors in areas with reported Zika outbreaks are similar to those found in Nigeria and would thus favour the circulation of Zika.
"Possible cross-reaction with other endemic flaviviruses like yellow fever and dengue; genetic host factors protecting against infection or disease; low vector competence and transmission efficiency; lack of diagnostic testing; and the absence of systematic surveillance are potential limitations to detect on-going transmission of Zika in Nigeria', the report added.
"In the light of above, NCDC plans to initiate surveillance to understand and monitor the epidemiology of Zika virus in Nigeria for the appropriate interventions."
The report also recommended that travellers should be informed of preventive measures before, during and after travelling to areas with Zika transmission.
Intending travellers should also be provided up-to date information of areas with ongoing Zika virus, it concluded.
WASHINGTON, Nov. 8, 2016 — A clinical trial began here yesterday at the Walter Reed Army Institute of Research, where 75 participating healthy adults were vaccinated with a Zika virus vaccine that the institute’s scientists developed earlier this year, Walter Reed officials announced today.
Laboratory-confirmed Zika virus disease cases reported to ArboNET by state or territory as of Nov. 2, 2016. ArboNET is a national surveillance system for arthropod-borne virus diseases in the United States, such as those from ticks and mosquitoes. Centers for Disease Control graphic
The Phase 1 trial will test the safety and immunogenicity -- the ability of the vaccine to trigger an immune response in the body -- of the purified, inactivated Zika virus vaccine called ZPIV. The vaccine is being tested at WRAIR’s Clinical Trial Center in Silver Spring, Maryland.
“The Army has moved efficiently from recognizing Zika virus as a threat, producing ZPIV for use in animals and demonstrating its effectiveness in mice and monkeys, producing ZPIV for human testing, and now initiating clinical trials to establish its safety and build the case for subsequent efficacy trials,” Army Col. (Dr.) Nelson Michael, director of WRAIR’s Military HIV Research Program, or MHRP, and Zika program co-lead, said in a statement.
Efficacy refers to the vaccine’s ability to demonstrate a health effect when tested in a clinical trial.
“All of this,” he added, “was done in 10 months.”
Dr. Kayvon Modjarrad, Zika program co-lead and associate director for emerging infectious disease threats at WRAIR’s MHRP, said the Army was able to move so quickly in developing, manufacturing and testing a Zika vaccine “because of its extensive experience with this vaccine platform and longstanding investments in the understanding and mitigation of flaviviruses like yellow fever, dating back to the founding of WRAIR.”
DoD Zika Response
WRAIR officials say this study is part of the Defense Department response to the ongoing Zika outbreak in North and South America and Southeast Asia.
For service members, there are concerns about infection during deployment and travel, but also in the continental United States, where most military installations are concentrated in southern states. There, climate conditions and mosquito populations favor Zika transmission, WRAIR officials say.
Zika virus is transmitted to people primarily through the bite of an infected Aedes species mosquito -- Aedes aegypti, shown here, and Aedes albopictus. The same mosquitoes spread dengue and chikungunya viruses. The mosquitoes typically lay eggs in and near standing water in things like buckets, bowls, animal dishes, flower pots and vases. They prefer to bite people and live indoors and outdoors near people. Mosquitoes that spread chikungunya, dengue, and Zika are aggressive daytime biters, but they can also bite at night. Mosquitoes become infected when they feed on a person already infected with the virus. Infected mosquitoes can then spread the virus to other people through bites. CDC photo by James Gathany
As of Nov. 2, according to the Centers for Disease Control and Prevention, 149 cases of Zika infection were confirmed in the military health system, including four pregnant service members and one pregnant family member.
Zika infection during pregnancy, CDC says, can cause a birth defect of the brain called microcephaly and other severe fetal brain defects.
But even Zika infections without symptoms “can lead to severe birth defects and neurological complications,” Zika study principal investigator Army Maj. (Dr.) Leyi Lin said, adding, “A safe and effective Zika vaccine that prevents infection in those at risk is a global public-health priority."
Zika and Other Flaviviruses
Flaviviruses like Zika are found mainly in mosquitoes and ticks and cause widespread morbidity and mortality worldwide. Other mosquito-transmitted viruses that are members of the flavivirus genus include yellow fever, or YF, dengue fever, Japanese encephalitis, or JE, and West Nile viruses, according to the CDC web page.
"We want to assess the safety and immune response of the ZPIV vaccine in JE and yellow fever YF vaccine recipients because these vaccines may alter the response to the ZPIV vaccine,” Lin said.
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VIDEO | 03:04 | Race for the Zika Vaccine: The Army Advantage
“Uniquely,” he added, “illness as a result of natural infection from JE, YF or Zika could be more severe when prior flavivirus infection or vaccination exists. Our study assesses co-vaccination to learn how to reduce risk when protecting against circulating flaviviruses.”
This is important for service members who are vaccinated against other flaviviruses and then stationed in or deployed to areas where Zika is becoming endemic, WRAIR scientists say.
Zika Vaccine Platform
WRAIR’s inactivated flavivirus vaccine platform was the same technology the institute used to create its Japanese encephalitis vaccine, licensed in 2009.
An earlier preclinical study found that rhesus monkeys vaccinated with ZPIV developed a strong immune response and were protected against two strains of Zika virus.
The National Institute of Allergy and Infectious Diseases, or NIAID, part of the National Institutes of Health, helped identify the viral strain used in the ZPIV vaccine, supported the preclinical safety testing and is sponsoring the conduct of this trial.
WRAIR, NIAID and the Department of Health and Human Services’ Biomedical Advanced Research and Development Authority, or BARDA, have established a joint research collaboration agreement to support the vaccine’s development.
The Pilot Bioproduction Facility at WRAIR manufactured the ZPIV vaccine being used in Phase 1 clinical studies, and the Army recently signed a cooperative research and development agreement to transfer the ZPIV technology to Sanofi Pasteur to explore larger-scale manufacturing and advanced development. BARDA recently awarded a six-year contract to Sanofi Pasteur to further develop this vaccine to licensure, according to the WRAIR release.
Transmission electron microscope image of negative-stained, Fortaleza-strain Zika virus, in red, isolated from a microcephaly case in Brazil. National Institutes of Health photo
Other ZPIV Trials
WRAIR’s ZPIV candidate also will soon be part of an NIH trial that began in August. The NIH vaccine contains DNA that instructs volunteers’ cells to make certain Zika proteins that then illicit an immune response. As part of that study, WRAIR’s ZPIV vaccine will be given to volunteers as a booster after they receive the NIH DNA vaccine, WRAIR officials say.
Three more Phase 1 trials using ZPIV are scheduled to begin this year, the WRAIR release noted:
-- St. Louis University researchers, through the NIAID-funded Vaccine and Treatment Evaluation Units network, will examine the optimal dose of the vaccine to be used in larger studies.
-- Beth Israel Deaconess Medical Center and Harvard Medical School researchers will evaluate the safety and immune response from a compressed vaccine schedule.
-- The Ambulatory Center for Medical Research, part of Ponce Health Sciences University in Puerto Rico, will examine the vaccine’s safety and immune response in participants who have already been naturally exposed to Zika or dengue viruses.
The WRAIR trial that began yesterday is sponsored by NIAID and funded by the Army and the Defense Department.
(Follow Cheryl Pellerin on Twitter @PellerinDoDNews)
