Speaking of Medicine

Karagiannis-Voules D-A, Scholte RGC, Guimarães LH, Utzinger J, Vounatsou P (2013) Bayesian Geostatistical Modeling of Leishmaniasis Incidence in Brazil. PLoS Negl Trop Dis 7(5): e2213. doi:10.1371/journal.pntd.0002213

New articles publishing in PLOS Neglected Tropical Diseases:

The occurrence of dengue fever and dengue hemorrhagic fever has increased in Brazil, in part due to the simultaneous circulation of DENV-1, DENV-2 and DENV-3, with severe outcomes being reported with some pregnant patients. Dr. Carolina Machado and colleagues analyzed available data compiled between 2007 and 2008 and discovered that pregnant women are 3-4 times more prone to developing severe dengue symptoms than non-pregnant patients.

Understanding the transmission of leishmaniasis in Brazil is essential to prevention and control efforts. Dr. Dimitrios-Alexios Karagiannis-Voules and colleagues used reported leishmaniasis incidence data in Brazil covering the period between 2001 and 2010 to explore the association of the disease with climatic, environmental, and socioeconomic variables, and to predict its spatial distribution using Bayesian geostatistical models.

Burkholderia pseudomallei is the etiologic agent of melioidosis and classified as a Tier 1 select agent due to the threat of malicious use of the organism. In the face of inherent multidrug resistance new therapeutic strategies are urgently needed to improve patient survival and to protect against a deliberate release. In this article, Dr. Saja Asakrah and colleagues identify the PGE2 pathway as an immunotherapeutic target in pulmonary melioidosis and show that post-exposure COX-2 inhibition provides significant protection against lethal B. pseudomallei lung infection in mice.

New articles published in PLOS Pathogens:

Bacteria have a distinct metabolism, part of which results in the production of bacteria-specific volatile organic compounds (VOCs), which might be used for diagnostic purposes. In this review, Dr. Lieuwe Bos and colleagues argue that goal-targeted studies should be performed to identify potential sets of volatile biological markers and evaluate the diagnostic accuracy of these markers in critically ill patients.

Surveillance data indicate that most circulating A(H1N1)pdm09 influenza viruses have remained antigenically similar since they emerged in humans yet antigenic drift is likely to occur in response to increasing population immunity. Dr. Teagan Guarnaccia and colleagues demonstrate this virus’s ability to undergo rapid antigenic change to evade a low level vaccine response, while remaining fit in a ferret transmission model of immunization and infection.

Malaria is caused by a parasite that grows within red blood cells, eventually rupturing them to release invasive merozoites in a process known as egress. Inhibition of the Plasmodium falciparum cGMP-dependent protein kinase (PfPKG) prevents egress, but the underlying mechanism is unknown. Here Dr. Christine Collins and colleagues clarify egress and show that both malarial PKG and parasite phosphodiesterases are potential targets for new antimalarial drugs.

PLOS NTDs editor-in-chief Peter Hotez highlights the subject of Female Genital Schistosomiasis in Africa that continues to affect women there heavily, yet receives disproportionally little attention.

Last month, together with Prof. Paul Brindley I wrote about new advances in the study of schistosomiasis caused by Schistosoma haematobium, best known as the cause of urinary tract schistosomiasis and bladder cancer in Africa.  Our article highlighted new animal models, the development of in vitro systems, and the recent completion of the S. haematobium genome leading to recent insights into parasite-induced carcinogenesis.  Compared to the other schistosomes S. haematobium has been relatively neglected by the scientific community in terms of number of citations in the scientific literature, especially since it is the world’s most common schistosome responsible for approximately two-thirds (actually 67%) of the schistosomiasis cases in sub-Saharan Africa where more than 90% of the disease burden occurs.

Mbabazi PS, Andan O, Fitzgerald DW, Chitsulo L, Engels D, et al. (2011) Examining the Relationship between Urogenital Schistosomiasis and HIV Infection. PLoS Negl Trop Dis 5(12): e1396. doi:10.1371/journal.pntd.0001396

In this and several other articles published in PLOS Neglected Tropical Diseases since 2009 we have tried to consistently emphasize the disproportionate impact of S. haematobium infection on girls and women.  Schistosome eggs embolize to the  uterus, cervix, and lower genital tract of girls and women to form fibrotic nodules known as “sandy patches” that result in a condition known as female genital schistosomiasis (FGS), which is associated with bleeding and pain (especially during sexual intercourse), as well as social stigma and depression.  I have also written about FGS in the lay press.

Some preliminary calculations provide cause for concern about the high prevalence of FGS.  Using the World Health Organization’s conservative estimate of 235 million cases of schistosomiasis or revised estimates from Prof. Charles King of 586-659 million people living with some form of schistosomiasis, and the fact that more than 90% of the global cases occur in sub-Saharan Africa, we can determine that between 200 million and 600 million people suffer from schistosomiasis in sub-Saharan Africa.  Assuming an equal sex distribution these numbers equate to approximately 100-300 million girls and women affected by schistosomiasis.  Using the 67% number for the percentage of cases caused by S. haematobium, there are approximately 67-200 million cases of S. haematobium infection among girls and women.  Further estimates that between 33%% and 75% of girls and women with S. haematobium infection also suffer from FGS in their lower genital tract would indicate that between 20 million and 150 million girls are affected, possibly making FGS one of the most common gynecologic conditions in sub-Saharan Africa where it is a horrific and widespread cause of bleeding, pain, depression, and stigma.
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