Malaria, tuberculosis caused death on the ancient Nile

 

Nile

Southwest of Cairo, the Nile branches into a network of canals that feed Fayum, a fertile agricultural basin that was a center of civilization and royal pyramid-building for several centuries. The unusual geology responsible for Fayum’s rich terrain may have also led to the prevalence of malaria and tuberculosis in the region during these ancient times.

Ancient DNA (aDNA) from sixteen mummified heads recovered from the region reveals that at least four of these individuals suffered both these infections simultaneously. Many of the others showed signs of infection with either malaria or tuberculosis, as scientists report in a recent PLOS ONE study.

DNA extracted from muscle tissue samples was tested for the presence of two genes specific to Plasmodium falciparum, the malarial parasite, and another gene specific to Mycobacteria, which cause tuberculosis. Two samples tested positive for DNA specific to Plasmodium, one tested positive for the mycobacterial gene, and four individuals tested positive for DNA from both infectious agents, suggesting they suffered both infections together while alive. A previous study suggests that both malaria and tuberculosis were rampant in the Fayum region in the early 19th century, but the age of these mummified samples extends evidence of these diseases in Lower Egypt as far back as approximately 800 B.C.

The World Health Organization estimates that malaria is almost non-existent in the Fayum basin and the rest of Egypt now, but before its eradication, high levels of infection were seen in certain parts of the country, and were strongly linked to certain geological features. The lakes and canals that made the Fayum region so fertile also served as breeding grounds for the mosquito that carries the malarial parasite.

The heads tested here (all were missing bodies) were recovered from a village cemetery on the west bank of the lower Nile, and date from about 1064 BC to 300 AD, a period marked by an agricultural boom and dense crowding in the region, especially under the rule of the Ptolemies. These conditions may have increased the chances of tuberculosis incidence and spread of the disease. As the aDNA from these mummified heads attests, these living conditions and the unique irrigation of the Fayum basin likely created a harbor for both malaria and tuberculosis in ancient populations of this region.

Citation: Lalremruata A, Ball M, Bianucci R, Welte B, Nerlich AG, et al. (2013) Molecular Identification of Falciparum Malaria and Human Tuberculosis Co-Infections in Mummies from the Fayum Depression (Lower Egypt). PLoS ONE 8(4): e60307. doi:10.1371/journal.pone.0060307

Image: Sailing on the Nile by David Corcoran

World Malaria Day 2013: Invest in the Future: Defeat Malaria

Anopheles

Since World Malaria Day was first instituted in 2007 by World Health Organization Member States, great progress has been made in malaria prevention, detection and treatment. Even so, over half a million people die each year from this disease, many of them children under five years old, with direct costs of the disease estimated to be in excess of $12 billion annually. Today, many countries worst affected by malaria transmission are on track to meet the 2015 World Health Assembly target of reducing incidence rates by more than 75% but continued research and support are vital to keeping this momentum.

Papers published recently in PLOS ONE highlight some of the work being done around the world to reach this goal and sustain the progress that has been made. A case study of Sri Lanka’s malaria program showed how better vector control and surveillance measures can substantially reduce malaria cases, and offers insight for the development of successful disease prevention campaigns in other countries.

In addition to control and detection measures, efforts to develop inexpensive treatments and efficient ways to produce vaccines continue to be important in the fight against malaria. Medicines derived from the extract of the Artemisia plant are widely used in malaria treatment, but in a paper published in PLOS ONE last year, researchers found using the whole Artemisia plant to be effective in malaria treatment in a mouse model. They propose that whole plant treatment may even offer a more efficient delivery mechanism, potentially having broad therapeutic power against many infectious agents and the ability to dramatically reduce treatment costs.

In another study, researchers from University of California, San Diego looked for a way to make safe and effective subunit vaccines less expensive to produce. They tested whether Plasmodium falciparum surface proteins 25 and 28, both powerful malaria transmission blocking vaccine candidates, could be produced on algal chloroplasts. Their work found algae a viable, cost-effective platform for producing malaria subunit vaccines, which could be a promising contribution in making these vaccines available to low-income countries.

These papers and many others support this year’s World Malaria Day theme to “Invest in the Future: Defeat Malaria.” As researchers continue to make strides towards the 2015 Millennium Development Goal to “have halted and begun to reverse the incidence of malaria,” you can read more PLOS ONE research on malaria here.

 

Citations: 

Abeyasinghe RR, Galappaththy GNL, Smith Gueye C, Kahn JG, Feachem RGA (2012) Malaria Control and Elimination in Sri Lanka: Documenting Progress and Success Factors in a Conflict Setting. PLoS ONE 7(8): e43162. doi:10.1371/journal.pone.0043162

Elfawal MA, Towler MJ, Reich NG, Golenbock D, Weathers PJ, et al. (2012) Dried Whole Plant Artemisia annua as an Antimalarial Therapy. PLoS ONE 7(12): e52746. doi:10.1371/journal.pone.0052746

Gregory JA, Li F, Tomosada LM, Cox CJ, Topol AB, et al. (2012) Algae-Produced Pfs25 Elicits Antibodies That Inhibit Malaria Transmission. PLoS ONE 7(5): e37179. doi:10.1371/journal.pone.0037179

Image: Anopheles by James Gathany for CDC

A selection of influential PLOS ONE papers on tropical medicine and malaria

For the XVIII International Congress for Tropical Medicine and Malaria Conference in Rio de Janeiro, PLOS ONE is highlighting eight recent articles.  Since January 2011, PLOS ONE has published almost 700 articles in the areas of tropical neglected diseases, tropical medicine, and malaria.  We’re sharing with you some of the papers that have received the most attention.  The authors on these papers come from across the globe, representing Brazil, Colombia, Ethiopia, France, the Netherlands, Papua New Guinea, Spain, Sri Lanka, Switzerland, the United Kingdom, and the United States.

One paper in particular has stood out.  Researchers found a novel therapy that could revolutionize the treatment of viral infections from the common cold to Ebola.  The therapy eliminates cells that contain viral RNA while leaving uninfected cells unharmed.  In the study, the therapy was effective against 15 different viruses, including dengue flavivirus, rhinoviruses, and H1N1 influenza virus.

An article published last month reported that malaria incidence in Sri Lanka has declined by 99.9% since 1999, despite ongoing conflict in the country.  The success of the malaria program could be explained in part by effective prevention measures, early detection, and maintaining the program in conflict zones.  In less than a month, the paper has received over 1,000 views.

Bacteria on people’s skin can affect how attractive they seem to malaria-transmitting mosquitoes.  Research published last December found that malaria mosquitoes preferred people whose skin had an increased number of bacteria but fewer overall types.  The article received significant press coverage and has been viewed almost 10,000 times.

Although a vaccine that blocks malaria transmission is theoretically possible, several obstacles have prevented its development, including producing Plasmodium parasite antigens in a cost-effective manner.  A paper published in May 2012 showed algae can make Plasmodium proteins that can elicit an antibody response.  This approach could bring down overall costs of a vaccine.  Since publication this paper has been viewed over 3,500 times.

A different approach to combatting malaria is to increase the mosquito’s defenses against the parasite.  A paper published in January 2011 showed that it is possible to insert an anti-malarial gene into a specific location in the Anopheles gambiae genome.  This technique decreased infections of Plasmodium yoelii nigeriensis and could be effective against other Plasmodium parasites.  Since publication this paper has received over 2,000 views.

The results from a World Health Organization-led effort to estimate the global incidence of leishmaniasis, a parasitic disease spread by sandflies, published in May 2012.  To obtain an accurate estimate of the disease burden, the authors collected data from 98 countries and 3 territories.  The authors stressed the importance of this in-depth assessment in helping policy makers and aid organizations determine funding priorities for this underreported disease.  The paper has been viewed over 5,000 times.

One strategy parasites use to evade the host’s immune system, initiate infection, and even manipulate host behavior is to imitate the host’s proteins.  A study published in March 2011 presented a method for scanning entire parasite genomes to identify proteins that are mimicking host proteins.  The paper received over 4,000 views and was featured on the This Week in Parasitism podcast.

Finally, a new method for diagnosing infection by Schistosoma mansoni, the parasite that causes schistosomiasis, was published in June 2012.  This method, which is based on detecting the parasite’s DNA, provides greater sensitivity than the most routinely used diagnostic approach, requires only a urine sample, and has a relatively low cost.

If you are at the ICTMM, we hope that you have had a chance to stop by the PLOS booth, pick up one of the PLOS ONE postcards, and meet staff from PLOS Pathogens and PLOS Neglected Tropical Diseases.

Acknowledgment:  Thank you to Martin Fenner for helping us use the PLOS Article Level Metrics to identify influential PLOS ONE papers in the areas of tropical neglected diseases, tropical medicine, and malaria.