Impoverished countries, which lack funding, education and access to proper medical care, are often plagued by viruses and diseases that have long been cured in the West.
In a special edition of "20/20," we take a look at three technological inventions that are helping to solve some of the world's worst health problems: the Camel Caravan in Kenya, GeneXpert in Cambodia and Embrace Infant Warmers in India.
This story is part of ABC News' "Be the Change: Save a Life" initiative, a year-long series of broadcasts and digital coverage focusing on global health issues.Click here to watch the special.
For complete coverage and information on how you can personally make a difference, go to SaveOne.net.
In the vast, barren land of Northern Kenya, roads are often nonexistent and temperatures can climb into the triple digits. These conditions make it extremely hard to deliver vaccines and supplies, especially to the nomadic Samburu people.
The World Health Organization (WHO) estimates that about 23 percent of people in Kenya don't have basic vaccines.
ABC News' Jay Schadler reported from the region on the novel idea of delivering medical supplies off the backs of camels instead of trucks.
Camels make the perfect mobile medical unit because they can go great distances without food or water. They're acclimated to desert life and they can carry up to 200 pounds.
Donna Thorson, a retired Boeing engineer, said she became aware of the Samburu people while vacationing in Kenya. After seeing the Camel Caravan, she decided to expand on the idea with one of her own -- a battery-powered refrigeration pack that fits onto a camel saddle.
Thorson described her system as simply a refrigerator, hooked-up to a battery pack that hangs on a traditional camel saddle. Lightweight, pliable solar panels are used to charge the batteries. The system is able to keep vaccines and other drugs refrigerated for hours -- not an easy feat in such a harsh climate.
"What I'm trying to do is take some of my money and my time and actually make a difference somewhere," Thorson told ABC News.
Although the idea of a solar-powered refrigerator is nothing new, Thorson said other models have "never worked out here" for several reasons.
Older solar panels were too fragile and too heavy to work with, and other refrigeration units often broke down from the pounding movement of the camel's gait. Also, the batteries that were used were usually too heavy or bulky to be carried great distances.
Last October, the WHO upgraded the standards for proper vaccine storage conditions, which made the previous refrigeration units unacceptable for sanctioned use.
After a year of research and field testing, Thorson developed her refrigeration system, which had to be proven to work before it could get WHO approval. She said she purposefully tried to "keep it simple," and was very conscious of the rigors of travel in a desert environment.
Ironically, her biggest inspiration for her system came from the oceans -- the refrigerator she chose was built to be used on boats. Thorson said she figured if it could survive being knocked around on the high seas it could probably handle riding on the back of a camel.
"Now it will be on the ship of the desert," she said.
Thorson also used a U.S. military-developed battery that would be powerful enough to keep the unit charged for many hours without power interruptions, but small enough to fit on the camel comfortably. This was important for keeping the medicine safe for use.
"It needs to stay between 35 and 45 degrees Fahrenheit, because otherwise you will destroy the vaccine," she explained. "Too high or too low, you're dead, it's over."
The most significant improvement Thorson made over older models was the use of cutting-edge, pliable solar panels to charge the batteries. According to Thorson, these panels were originally designed for the U.S. military to be used on rooftop security cameras in Iraq.
Thorson said the new panels provide power for extended periods of time so soldiers don't have to risk their lives to constantly change the batteries.
They were perfect for Thorson's purposes too. She said the panels can provide potentially limitless power to her system and can be folded for easy travel. Also, they can survive in the inhospitable desert environment.
Finally, she designed her unit to fit on a wooden camel saddle native to that region of Kenya. This was done so no one would have to buy new saddles to use the system and the camels would already be used to what's on their backs.
"The goal is eventually to have five routes and the camel clinics go through each route once a month," she said.
Although Thorson is currently using her own money for her design, she said a British company is considering manufacturing and marketing her system worldwide, pending approval from the WHO. If that works out, Thorson said she would plan on donating her share of the profits to fund the camel caravan in Kenya.
Tuberculosis still kills 1.7 million people annually worldwide, and Asia has the highest number of TB and multiple drug-resistant (MDR) TB cases, according to the World Health Organization. It's a disease that has been nearly wiped out in the West.
ABC News' Dan Harris reported on TB cases in Cambodia. It's a country with one of the highest rates of TB incidence in the world, because a large number of people suffer from HIV and already have weakened immune systems.
One big problem: patients often have to wait weeks for test results to be processed, if they decide to go get tested at all. The average untreated MDR TB patient infects 12-15 people in his or her lifetime. It can be spread by an infected person coughing in a heavily-populated area.
"If you don't catch it early, people are coughing ... it's a very dense area," said Dr. Anna Goldfeld, a professor at Harvard Medical School who has been studying the impact of infectious diseases and treating Cambodia's TB and HIV patients for two decades.
Now there is new hope in fighting TB. GeneXpert MTB/RIF is a revolutionary diagnostic tool that can test for TB and drug resistance in two hours -- a novel and important improvement to the old tests. Developed by Cepheid, a California company, GeneXpert analyzes the genetic makeup of a sputum sample to determine if the patient is infected with TB.
GeneXpert was originally developed with input from the Pentagon to test for Anthrax. It resembles a coffee machine, and costs around $20,000.
After the WHO endorsed the use of GeneXpert, Cepheid said it would offer a 75 percent price cut to countries with the highest number of TB cases. The public can also donate to the cause.
"For $20, you can buy one cartridge for the GeneXpert machine that would allow us to diagnose TB in an adult or a child really rapidly," Goldfeld told ABC News.
Despite being one of the fastest-growing and largest economies in the world, India's infant mortality rate is incredibly high, especially for premature babies.
According to Save the Children, more than 400,000 babies die in India within the first 24 hours of life every year.
ABC News' Elizabeth Vargas reported on a team which developed the Embrace Infant Warmers while they were students at Stanford's Institute of Design.
The product is an inexpensive, low-tech device that looks like a small sleeping bag. It regulates a baby's body temperature using a wax insert that can be safely reheated.
Incubators are vital to premature babies' survival because their internal organs are not fully developed at birth.
"These babies are so tiny they don't have enough fat to regulate their own body temperature," said Jane Chen, co-founder and CEO of Embrace. "In fact, room temperature feels like freezing cold water to them."
The "Be the Change: Save a Life" initiative is supported in part by the Bill & Melinda Gates Foundation.