Beginning in 1966, Henderson led a global effort based at the World Health Organization (WHO) to accelerate smallpox vaccinations. In an extraordinary campaign that required vaccinating people in the poorest and most remote areas of the world (and detailed in his book Smallpox: The Death of a Disease), the disease vanished, with the last known naturally transmitted case of smallpox occurring in 1977.

Ever since, we have made great strides in the global control of infectious diseases, and even progress towards disease eradication, but frequently the endgame has been disrupted by an unexpected turn of events. In a recent book, I estimated that most of the world’s poverty-related neglected diseases are paradoxically found in the G20 nations. There are at least a half dozen diseases for which disease elimination or eradication would be feasible were it not for war or national turmoil, political malaise, or a growing anti-vaccine movement.

Some of the most dramatic examples of game-changing disruptions in disease control have been noted for human parasitic and tropical infections. During much of the 20th century, tremendous strides were made in the elimination of the highly lethal Gambian form of African sleeping sickness (human African trypanosomiasis or “HAT”) through a combination of case detection and treatment and tsetse fly control. Many of the methods used to wipe out sleeping sickness were developed by Dr. Eugene Jamot, a French physician working in Cameroon who pioneered the use of portable and movable treatment teams during the early 20th century.

By the 1960s, Gambian HAT was near elimination in many African nations. But when hostilities and civil and international conflicts broke out in Angola, Democratic Republic of Congo, Sudan, and elsewhere, public health control was interrupted, so that by the 1990s the incidence of HAT had returned to pre-Jamot era levels. More recently, as tensions have eased and mass treatment and tsetse control efforts have been reinstated, we have seen a 73 percent reduction in deaths from HAT between 1990 and 2010. With only about 10,000 cases of HAT remaining, we may still yet see the global elimination of this deadly disease.

War, conflict, and political instability also have halted or interrupted other global efforts to eliminate or eradicate parasitic diseases. Breakdowns in health systems in Venezuela are resulting in resurgences of malaria and Chagas disease. Public health disruptions from the ISIS occupation of Syria and Iraq have allowed the number of cases of cutaneous leishmaniasis, a disease transmitted by sandflies and often associated with a disfiguring ulcer on the face, to skyrocket and spread into neighboring countries. The only good news is that although wars in the Sudan almost derailed global guinea worm eradication efforts led by the Carter Center, the Centers for Disease Control, and WHO, through the perseverance of these organizations, this disease may soon become only the second disease ever eradicated .

Next to war and political instability, probably the next most corrosive factor thwarting public health gains against infectious disease is simple absence of political will. During the 1950s and ‘60s, under the auspices of the Pan American Health Organization, an ambitious effort to control yellow fever and dengue resulted in the eradication of the Aedes aegypti mosquito in more than a dozen Latin American and Caribbean countries. But lapses in mosquito control efforts and other factors allowed Aedes aegypti to reestablish, resulting in the reintroduction of dengue into the region during the 1980s. Now yellow fever has returned to Brazil, where it could gain access to Aedes mosquito populations and threaten urban centers.

Perhaps the most disheartening examples of infectious disease control going off the rails are instances in which there are deliberate attempts to block vaccination efforts. Today, the transmission of polio has been halted everywhere except in Afghanistan and Pakistan (and before that northern Nigeria) due in part to concerted efforts by religious extremist groups to kidnap or assassinate vaccine workers.

And now in the United States and Europe we have anti-vaccine groups who allege links between vaccines and autism, despite massive scientific data showing conclusively there are no links or even any plausibility for vaccines causing autism.

A particular concern is the resurgence of measles, because it is one of the most contagious of all the vaccine-preventable diseases and often is the first to re-emerge following a decline in vaccine rates. But really any one of the major childhood illnesses targeted for vaccination could re-appear. Measles was eradicated in the United States in 2000. However, it returned to California in 2015, and now the state of Texas is especially vulnerable because tens of thousands of children are not being vaccinated for non-medical exemptions. Globally, between 1990 and 2010 there has been an 80 percent decline in measles deaths and for the first time the number of young children who die of measles globally has dropped below 100,000. However, there are concerns that an American-led anti-vaccine movement could now derail this achievement and possibly even lead to a reversal of sustainable and global goals for health and poverty reduction.

We need a concerted effort by global leaders to close current gaps and explore final steps to eliminate our great plagues. To do so will require international cooperation by the WHO member states, especially the 20 wealthiest economies comprising the G20 nations. Taking on the considerable political and social hurdles will become one of the great international challenges in freeing populations from the tyranny of epidemics or pandemics.

The post To End Infectious Disease, We Must Cure Our Societal Ills appeared first on Zócalo Public Square.

They showed me a single female mosquito under the microscope. It didn’t look good: I focused up and down, trying desperately to make the black and white stripes on her legs and the white “ax mark” on her thorax disappear.

“Where did you find her?” I asked.

“El Monte,” Marc said sadly. “A woman complained about being bitten during the day by mosquitoes, and I caught this one at her home.”

It was September 2, 2011. We thought Aedes albopictus had been eradicated from Los Angeles for 10 years, but these nasty vectors were back—and we were about to learn a hard lesson about the difficulty of controlling them. These days, controlling mosquitoes in North America is part of a larger Faustian bargain: We are free to travel and shop around the world, but without geographic barriers, exotic pests and viruses invade our shores. How can we be vigilant about these risks, without losing our minds about every foreign-sounding bug and virus?

Aedes albopictus (“albos” for short) is a mosquito that keeps vector control officers up at night, especially with the attention mosquito-borne Zika virus is garnering as it moves through Brazil, Latin America, and the Caribbean. Mosquitoes of the genus Aedes, including “albos,” are the ones in the U.S. capable of transmitting chikungunya, dengue, and Zika virus, all of which cause serious human diseases.

Worse, these black-striped mosquitoes are not shy about their love for humans: They prefer feeding on us and bite relentlessly during the day, enhancing the risk that they will spread viruses like Zika from the infected to the uninfected.

Finally, “albos” are difficult to control because they need only the tiniest amount of water—as little as a bottle cap full or a space between the leaf and stem of a plant—and their eggs survive a drought for a year or more.

California has been organizing programs to control mosquitoes for about 110 years, since 1909. Early programs fought malaria and in the 1940s and ’50s, the state formed many mosquito abatement districts when Western equine encephalomyelitis and St. Louis encephalitis viruses sickened hundreds of people and killed thousands of horses in the Central Valley. Since 2004, vector control agencies have waged a continuous battle against West Nile virus.

In 2001, Aedes albopictus, the “Asian tiger mosquito” arrived in California as a stowaway that arrived in shipments of popular plants marketed as “lucky bamboo.” The shipments were mostly from southern China; stalks of the plants were placed in tubs of water and sent off by the container load. Their voyage across the Pacific was the perfect pleasure cruise for an invading insect. Before shipping, the containers sat open on the docks, and mosquitoes laid eggs in the tubs. The crossing allowed these eggs to hatch, and adult mosquitoes that were trapped when container doors were shut laid more eggs. When the containers were opened upon arrival, adult mosquitoes escaped, and the eggs were transported to “lucky bamboo” distribution centers.

Getting rid of that infestation took a massive effort by multiple agencies—the University of California, the state’s Department of Public Health, and members of California’s Mosquito and Vector Control Association were all involved. Regulations were enacted to ensure “lucky bamboo” was no longer shipped in standing water. For the next three years, no one found Aedes albopictus. We Californians were proud of being the first state to eradicate a large infestation these mosquitoes.

We surmised that southern California’s climate was too inhospitable for Aedes albopictus to easily gain a foothold, and the pressure we exerted on them caused their demise.

We were very wrong.

The genetics of the mosquitoes we collected in 2011 most closely resembled those from south China, where the infestation in 2001 originated. Somehow, Aedes albopictus had lived under the radar here in Southern California for a decade. Surveillance to detect small populations of these mosquitoes is difficult, so by the time we found them in 2011, they had infested a large area.

Because of our relative success in 2001, we started fighting 2011’s infestation brimming with confidence. Along with our colleagues from the Greater Los Angeles County Vector Control District, we worked in a furious effort to determine the outer limit of the infestation, remove sources of water, educate residents, and eradicate any mosquitoes that we found. Initially, our hopes were buoyed when the mosquitoes seemed to disappear as the days shortened and the weather cooled in November 2011. We looked forward to wiping out a few remaining pockets in the spring of 2012.

Famous last words. When spring came, “albos” emerged with a vengeance. Although we tried everything, Aedes albopictus doubled its range every year after that. We expect to find them in each of the 24 cities in our jurisdiction by the end of 2016. The drought that continues to plague southern California will have little effect on Aedes albopictus; they hardly need any water to develop, and even without water, their eggs will remain poised for months, waiting for the next rain to fall.

Towards the end of 2014, the fight against Aedes albopictus in Los Angeles County took an ominous turn when Aedes aegypti was discovered in the City of Commerce. Now, two of the world’s most infamous vectors were present in the county. Aedes aegypti’s common name, the “yellow fever mosquito” says it all. Its biology is similar to Aedes albopictus, but Aedes aegypti is considered the most versatile vector of all when it comes to transmitting human diseases.

To make matters worse, Aedes aegypti had also been found in several counties in the Central Valley, and in San Mateo County. 2015 was a banner year for both species of Aedes. By its end, Aedes aegypti or albopictus could be found in 12 counties and 76 cities in California. The possibility that chikungunya, dengue, and Zika viruses could be transmitted locally became reality for a good portion of the state. Of course, while there still are just pockets of these mosquitoes in California and other parts of the southwest, Aedes mosquitoes have made themselves quite at home in the southeastern U.S., with a range that goes out as far north as Connecticut and the Midwest, and much of Texas.

Still, it’s not likely that a widespread epidemic like Zika in the Caribbean, Central, and South America will occur in the U.S. The viruses are not transmitted when Aedes aegypti and Aedes albopictus stop biting during winter, and the viruses cannot live in hosts other than humans. This means chikungunya, dengue, and Zika viruses must be introduced to mosquitoes each year by infected humans.

Even though the Zika virus, which is associated with severe brain damage in babies born to infected mothers, is getting all of the attention, the mosquito-borne virus that we should really worry about is the deadly West Nile virus. Unlike Zika, West Nile virus lives primarily in birds and is continuously present, ready to infect humans. Last year there were 299 cases in Los Angeles County and 22 deaths. These numbers are high—especially for a disease that doesn’t get much press anymore—but there may really have been as many as 7,000 cases of West Nile in Los Angeles alone last year, based on statistics from 2015 and the CDC’s estimates of symptomatic illness. What will happen with West Nile virus in 2016 is not certain, but the prospect of dealing with an epidemic caused by that virus along with local outbreaks of chikungunya, dengue, or Zika greatly concerns all of us at vector control agencies.

Our biggest challenge will be getting Californians to change their behavior. No agency’s budget is sufficiently large to hire enough workers to get into everyone’s backyard. We must motivate residents to remove all the sources of water on their property that may produce mosquitoes.

This time, we might just get lucky. Californians are not used to mosquitoes, and the ferocious daytime bites of Aedes aegypti and Aedes albopictus will interrupt our famous outdoor lifestyle—making people uncomfortable enough to take action. In a state with a vector control system designed to protect public health, it’s ironic that the mosquitoes themselves, not the diseases they transmit, may deliver a more powerful message than any public information campaign.

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