Guest editor Bill Gates Can we eradicate some of the world’s worst diseases by 2030? By Arielle Duhaime-Ross

We're excited to have Bill Gates as our guest editor in February. Throughout the month, Bill will be sharing his vision of how technology will revolutionize life for the world's poor by 2030 by narrating episodes of the Big Future, our animated explainer series. In addition, we'll be publishing a series of features exploring the improvements in banking, health, farming, and education that will enable that revolution. And while the topics reflect the bets Bill and his wife Melinda are making with their foundation, they've asked us for nothing less than fully independent Verge journalism, which we're more than happy to deliver. Turns out Bill Gates is a pretty confident guy. Nilay Patel, Editor-in-Chief

The parasitic worms that cause river blindness give birth to 1,600 larvae each day. "I’ve heard people say that they feel this buzzing under the skin; they feel the little larvae under the skin and it’s itchy," says Elodie Ghedin, a molecular parasitologist at New York University. The larvae then travel to various parts of the body, including the eyes, where they cause inflammation and lesions when they die. Adult worms survive up to 15 years in a human host, nine of which are spent reproducing. The WHO estimates that 18 million people are infected with these parasites worldwide — in certain West African communities, about 50 percent of men over the age of 40 have been blinded by the disease. It’s a terrible illness — but it could be wiped "off the face of the Earth" within the next 15 years. In certain communities, about 50 percent of men over the age of 40 were infected with river blindness That’s the bet that Bill and Melinda Gates are making in their 2015 annual letter. It outlines how innovations in technology, medicine, and public health will serve to better the health of the world’s poor within the next 15 years. The Gates predict that vaccines and improved care for newborns will halve the number of children who die before the age of five. The number of mothers who die in childbirth will be reduced by two-thirds. More people will begin HIV treatment each year than will be diagnosed with HIV. We will eradicate infectious diseases like polio, guinea worm, river blindness, and elephantiasis. And by 2030, science will have found a way to eradicate malaria. "We think some very dramatic things can happen," Bill Gates told The Verge. These goals are ambitious. Despite a decline in new HIV infections worldwide, the World Health Organization estimates that over 2 million people tested positive in 2013. That year, the rate of children who died before the age of five in sub-Saharan Africa was double that of the worldwide average. And conflicts in countries like Syria have caused polio to surface in countries that eliminated the disease long ago. The truth is that any number of political, cultural, and environmental obstacles can derail a country’s health care progress. Yet, some developing countries have managed to make a prodigious amount of progress in a short amount of time. Here, we profile three developing countries — Uganda, Nepal, and Rwanda — that have considerably improved the lives of their citizens by focusing on key health concerns described in the 2015 letter from Bill and Melinda Gates. Can their success in reducing tropical disease transmission, maternal and infant mortality, and HIV infection rates in the face of tremendous adversity be replicated across the developing world?

The eradication of neglected tropical diseases represents a big chunk of the Gates Foundation’s goals for 2030. Parasitic diseases like river blindness can be devastating for the social and economic health of a community. But some countries, like Uganda, have garnered praise among the international health community for their work on these diseases — and they’re well on their way to eliminating them altogether. mass drug administration has helped interrupt river blindness transmissions in 14 of Uganda’s 16 disease hot spots "Uganda has done a tremendous job against river blindness," says Thomas Unnasch, a vector biologist at the University of South Florida who receives research funding from the Gates Foundation and chairs of Uganda’s river blindness elimination expert advisory committee. No vaccines against river blindness exist, but Ugandans living in areas where transmission occurs receive two doses of a drug that treats the infections each year. Unfortunately, the drug — called ivermectin — only kills the larvae, so people infected with the parasite have to wait until the adults die or become infertile before they can consider themselves "cured." In the meantime, ivermectin serves to alleviate symptoms and reduces transmission. Uganda’s ivermectin distribution program has been running since 1997 thanks to drug donations from pharmaceutical company Merck, and international aid. So far, mass administration of this drug has helped interrupt transmission in 14 of Uganda’s 16 disease hot spots. The country’s organized approach to drug administration is an important factor in the disease treatment there, Unnasch says. But that isn’t the only reason Uganda has done so well: the country’s geography, combined with the peculiarities of the blackfly species that carries the parasites there also contributed. "They have a vector that breeds only in the small streams," Unnasch says of the blackflies that transmit river blindness. To stop them from reproducing, workers treat small rivers once a year with an insecticide that is safe to humans. "They just put a line of insecticide in the river, and it kills all the blackfly larvae," he says. In other words, the blackflies are a lot easier to handle in Uganda than in many other countries where the vectors breed in large rivers. In those situations, killing off larvae in big quantities isn’t always feasible.

When it comes to maternal and child mortality rates, Nepal’s achievements stand out. Over the course of the last 10 years, the maternal mortality rate there has dropped by 40 percent. And Nepal decreased the number of children who die before the age of five by 72 percent since 1990. Although the number of child deaths is still very high — about 24,000 children under the age of five die each year — the improvements are undeniable. Maternal mortality ratio (modeled estimate, per 100,000 live births) Data from World Bank To address the health of Nepalese women and children, Nepal invested in its health care system. Between 2000 and 2010, the country tripled its health spending for each citizen, says Mariam Claeson, director of the Maternal, Newborn, and Child Health program at the Bill & Melinda Gates Foundation. The government further encouraged health care access by making conditional cash transfers to women who sought care from medical facilities, starting in 2005. And the government provided free health care to women living in a third of the country. As a result, the number of children who were born in a health care facility went from 19 percent to 45 percent in just five years, says Ramesh Adhikari, a professor of pediatrics at Kathmandu Medical College in Nepal — a change that likely ensured safer births for both mother and child. Nepal also focused on vaccines. In the last decade, the proportion of children who received annual vaccinations against tetanus, whooping cough, or a serious respiratory disease called diphtheria increased to 92 percent, from 75 percent. Foreign aid played a big role; in 2012, international organizations like GAVI and the WHO helped fund more than half the country’s routine immunizations. The result is that 9 out of every 10 infants received vaccinations for diphtheria and tuberculosis in 2012. The vaccinations have changed the country’s health care landscape: "When I started as a pediatrician 25 years back, we would see diphtheria disease, and now we don’t see it," says Adhikari, who is also a chairman for national committee on immunization practices. Mortality rate, under-5 (per 1,000 live births) Data from World Bank Nepal’s focus on vaccines aligns with the Gates Foundation’s priorities. In 2013, the Foundation spent $338 million in grants related to improving vaccine delivery. These kinds of contributions can pay off: vaccines currently prevent 2 to 3 million deaths each year from diphtheria, tetanus, whooping cough, and measles, according to the WHO. But about 22 million infants continue to miss out on routine vaccines worldwide. The Gates Foundation and its partners want to change that by handing out vaccines against rotavirus, which causes diarrhea, and against pneumonia to "all kids" within the next five years, Gates says. "Those two alone will save over a half a million lives, and that’s why we think we can go from the 1 in 20 kids — 5 percent who die before the age of 5 now — to 15 years from now to get that down to be 1 in 40," he says. It’s a great idea, but getting vaccines to the children who need them by 2030 won’t be easy. The introduction of novel, expensive vaccines, combined with pharmaceutical company monopolies, means that the price of fully vaccinating a child is 68 times higher than it was 10 years ago, according to Doctors Without Borders. And that increase includes shots that protect against pneumonia-causing bacteria — bacteria that caused 935,000 children under the age of five to die in 2013, according to the WHO.

Sub-Saharan Africa is home to the worst HIV epidemic on the planet. About 70 percent of people who are living with HIV reside here. Despite that, countries like Rwanda are making improvements in the rate of new infections — and they’re doing it by overhauling their health systems and engaging their citizens. "Rwanda is the greatest success story in Africa, in terms of HIV, its health system, economy, and national stature," says Edward Mills, an epidemiologist at Stanford University who helped assess Rwanda’s health care system for the Gates Foundation. The nation’s HIV prevalence has been at a steady 3 percent since 2005, and the number of people diagnosed with HIV in Rwanda is declining — even though more people are tested each year. In 2007, about 37,000 Rwandans tested positive for HIV; by 2013, that number went down to 13,000. In 2007, about 37,000 Rwandans tested positive for HIV; by 2013, that number went down to 13,000 Rwanda’s ability to address its HIV infection rates is impressive. But it’s even more impressive considering the country’s recent history. In 1994, the country experienced a devastating genocide. An estimated 800,000 people died over a period of 100 days. "Every Rwandan was touched personally by the genocide," Mills says. In the aftermath of the tragedy, the country had to rebuild itself and its health care system, which Mills says was "essentially destroyed." The most important factor in Rwanda’s improvements is likely the government’s commitment to addressing HIV at all levels of the population, including the country’s most at-risk groups: sex workers and men who have sex with men. Right now, about 51 percent of sex workers in Rwanda are HIV positive. "What the government feels is that if they were to target those populations they could break the infection chain," Mills says. Despite the fact that sex work is criminalized in Rwanda, female sex workers and men who have sex with men are involved in designing surveys that explore HIV prevalence and risk factors that contribute to transmission in their communities. The country has "Female Sex Worker Coordination Committees" operating in eight of the country’s 30 districts. These committees — which include police, health service providers, government officials, and sex workers themselves — help implement HIV programs in the districts. The Rwandan government also commissions media campaigns to discuss HIV, Mills says, and actively discourages extramarital relationships. Finally, the country has drastically scaled up Rwandans’ access to HIV services. In 2009, fewer than half of its hospitals and health centers offered HIV testing, counseling, treatment, and methods that can prevent HIV transmission between mother and child. By 2011, those services could be accessed in 75 percent of facilities. As a result, the number of women and men who received HIV test results between 2005 and 2011 went from 1 in 10 to approximately 4 in 10. "Rwanda is not yet a success story," says Sabin Nsanzamana, head of the HIV, STI, and Other Blood Borne Infections Division at the Rwandan Ministry of Health. But Rwanda’s achievements demonstrate how powerful HIV interventions can be when there’s a willingness to employ them. Much like Nepal with maternal and infant mortality, Rwanda’s multi-pronged approach to HIV aligns well with the Gates Foundation’s goal of reaching an HIV "tipping point" by 2030 — a time when the number of new HIV infections that arise each year is surpassed by the number of people who are put on antiretroviral treatment. Rwanda could reach that goal "within two years," Mills says. That said, many of Rwanda’s advances are linked to the country’s history. "It seems that the community is pulling together to make a strong Rwanda," says Chris Dickey, a professor of global public health at New York University. The country’s 45,000 community health workers aren’t paid much, but they perform the work because they want to give back, he says. "A lot of that can be traced back to the agony that was felt by the entire country in 1994," he says. For that reason, implementing these interventions in other countries might not be all that straightforward. "It may or may not be a unique example," he says.