GlobeMed at CU Boulder

Phage Therapy in Infectious Disease

In recent years, there have been great advances in the field of phage research. Phages, as you might know, are ‘viruses’ that infect bacteria rather than animal or plant cells. Like viruses, they harness the genetic machinery of bacteria to reproduce and reinfect other cells. Unlike viruses, they can’t get you sick.

Since phages naturally prey upon bacteria, and typically infect specific bacterial species, they could presumably be used to treat infectious diseases like tuberculosis and tetanus. Phage therapy, though, is still a nascent field and much more research needs to be done before large-scale human testing can begin.

Still, phage therapy could offer a cheap and effective means of combatting disease. Since phages self-replicate, only a small sample would be needed to effectively manage a bacterial population. A study by Broxmeyer et al. (2002) showed that a small sample of phage-infected nonvirulent bacteria could be used as ‘Trojan horses’ to effectively deliver enough phage to eliminate cultures of tuberculosis. In addition, a study by Levin and Bull (2004) found that phage therapy for TB was highly effective when combined with multiple first-line antibiotics, and significantly decreased the rate of drug resistance.

For now, this is all a little sci-fi. In the future, though, phage therapy may emerge as a cheap and innovative way to combat unnecessary death by infection. 

Links to articles here and here.

Reinventing Eye Surgery in India

Yesterday’s NPR broadcast featured a fascinating story about the Aravind Eye Care System, a not-for-profit organization in south India that is working to prevent cataract blindness. This subject matter is of particular interest to me—my mother is an eye surgeon who works on strabismus and cataract patients in rural Peru—but more importantly gives us a powerful case study on how to balance economic needs with health equity. 

Cataract blindness is one of the most widespread preventable problems in the developing world. Like many other issues in health equity, cataracts develop more often and more quickly in the most structurally disadvantaged sectors of a society. The WHO writes,

“Worldwide, approximately 18 million people are blind as a result of cataracts, and, of these, 5% of all cataract related disease burden is directly attributable to UV radiation exposure.”

Thus, a farmer who spends all day working in his field without eye protection faces an increased risk of cataract blindness. The problem is also self-perpetuating, from an economic standpoint: blindness is highly debilitating in manual labor, so many of those who become blind are forced into retirement early. This leads back into a cycle of poverty, a chain which can be broken by a simple and relatively inexpensive procedure. The surgery itself is simple. A surgeon makes a small incision on the edge of the cornea and removes the natural lens, which has become opaque. He or she then inserts a new, synthetic lens in its place and sutures the incision. The problem? Synthetic lenses are expensive, and out of the income range of the people who most need the surgery.

Aravind’s founder, Dr. G. Venkataswamy, has approached this problem by blending business strategy with a charitable mission. This technique can be seen in many NGOs worldwide, to some degree, but what sets Aravind apart is its ability to vertically integrate the process of eye surgery—that is, to control every aspect of the process, from lens production to actual implantation. The organization even owns a lens manufacturing plant in India, called Aurolab. Accordingly, every step along the way is treating like a business, aimed at maintaining an operating surplus. 

Link to the full article here. For more information on cataract blindness, visit the WHO’s site here and here.

The Case for Essential Medicines

It’s well-known that the diseases of the ‘first world’ do not align with those of the ‘third world.’ Malaria, measles, polio—these became rare in the US even before our grandparents were born.

In the 2010 census, the average tuberculosis prevalence in the US was 5.8 per hundred thousand. That same year, Nepal’s prevalence was about 250 per hundred thousand. Pakistan saw rates as high as 325. We see similar prevalences among most of the world’s population; by the numbers, the first world citizens are in the great minority. It might not come as a surprise, then, that no new tuberculosis drugs have been developed since the mid-1970s. Malaria is in a similar state: though new antimalarials have been developed, the inexpensive types come with terrible side effects. Meanwhile, drugs to combat the issues of the first world—cancer, diabetes, heart disease—have boomed, both in terms of availability and profit margin.

Back in 2001, a team of health specialists led by Dr. Patrice Trouiller put together a great paper on the economics of drug development, making a case for why there has been so little innovation in drugs to treat tropical diseases. The basic answer? The demand is almost completely in the developing world, and the developing world can’t return the initial investment. This imbalance is crystallized in the figure below (Trouiller 2001).

Depressing? Maybe. But Trouiller et al. offer a solution: research policy reform. They call for certain drugs to be classified as ‘essential’—that is, the “neglected diseases” (948) such as tuberculosis, malaria, and measles, should be subsidized by international organizations like the WHO to be developed more cheaply. In addition, they argue that patent policy should be modified to make sure these crucial drugs can be developed in the countries that need them most. As we can see, the free market alone can’t fix this problem.

Link to the full article here.

Machisma: Girl Power in Brazil

Last month’s edition of National Geographic Magazine included a fascinating story by Cynthia Gorney on the lowering of the national fertility rate in Brazil. Fertility rates are deceptively simple statistics. Though they seem to be relevant only to population studies, they point to much larger forces. Fertility rates can tell you a lot about the status of women’s empowerment in a country. They can tell you how strong its health infrastructure is, and its pharmacy system. Because poor women are often the most structurally oppressed demographic in a given society, a fertility rate is a measure of how well a health system can connect to its most disenfranchised peoples.

Best of all, the article is a blast to read. Gorney writes:

“That new Brazilian fertility rate is below the level at which a population replaces itself. It is lower than the two-children-per-woman fertility rate in the United States. In the largest nation in Latin America—a 191-million-person country where the Roman Catholic Church dominates, abortion is illegal (except in rare cases), and no official government policy has ever promoted birth control—family size has dropped so sharply and so insistently over the past five decades that the fertility rate graph looks like a playground slide.

And it’s not simply wealthy and professional women who have stopped bearing multiple children in Brazil. There’s a common perception that the countryside and favelas, as Brazilians call urban slums, are still crowded with women having one baby after another—but it isn’t true … In a working-class neighborhood on the outskirts of Belo Horizonte, an unmarried 18-year-old affectionately watched her toddler son one evening as he roared his toy truck toward us; she loved him very much, the young woman said, but she was finished with childbearing. The expression she used was one I’d heard from Brazilian women before: “A fábrica está fechada.” The factory is closed.”

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Read the full article here