DR Congo and Nigeria: New neglected tropical disease threats and solutions for the bottom 40%

1 Texas Children’s Hospital Center for Vaccine Development, Departments of Pediatrics and Molecular Virology and Microbiology, National School of Tropical Medicine, Baylor College of Medicine, Houston, Texas, United States of America, 2 Center for Medical Ethics and Health Policy, Baylor College of Medicine, Houston, Texas, United States of America, 3 Department of Biology, Baylor University, Waco, Texas, United States of America, 4 James A Baker III Institute for Public Policy, Rice University, Houston, Texas, United States of America, 5 Scowcroft Institute of International Affairs, Bush School of Government and Public Service, Texas A&M University, Texas, United States of America


Funding:
The author received no specific funding for this work.
Competing interests: I have read the journal's policy and the authors of this manuscript have the following competing interests: I am lead investigator and/or patentholder on several vaccines in clinical trials or in development, vaccines which would provide protection against some of the infections and diseases discussed in the article such as hookworm and schistosomiasis.
have the world's highest incident number of cases of malaria [5]. The consequences of the geographic overlap and coendemicity of schistosomiasis, human hookworm infection, and malaria have been reported previously and include profound and incapacitating anemia, especially among children and women of reproductive age [6][7][8][9]. In addition to its important maternal-child health consequences, anemia also profoundly affects economic productivity [10]. We therefore can anticipate that anemia from the syndemic NTDs and malaria will continue to be a dominant theme for Nigeria and DR Congo in the 21st century.
While extreme poverty is probably the dominant factor in the persistence of NTDs in Nigeria and DR Congo, other drivers have been noted, including political instability and conflict in the region [11,12]. Although the mechanisms underlying these two factors on health require further study, undoubtedly, their ability to collapse health systems is paramount. We're now seeing this play out in North Kivu of Eastern DR Congo, where conflict hinders an international effort to control Ebola virus infection despite the availability of a new vaccine [13,14]. Our analyses find that conflict may rank second only to poverty as a modern driver of the NTDs [15]. Still other factors promoting the NTDs are malnutrition and food insecurity and climate change, especially for vector-borne NTDs [16].
In the coming decades, urbanization will become yet another important driver for NTDs in Nigeria and DR Congo. According to some projections, by the year 2050, Kinshasha in DR Congo will be the world's fourth largest city, with an estimated population of 35 million people, while Lagos, with over 32 million people, will be the sixth largest [17]. Among the consequences of urbanization-working together with poverty, food insecurity, climate change, and political instability-will be new urban foci of hookworm (and other soil-transmitted helminth infections), schistosomiasis, and possibly onchocerciasis; arbovirus infections transmitted by Aedes aegypti; canine rabies; and selected bacterial infections such as leptospirosis, cholera, and typhoid fever, to name a few [18].
There are concerns that the emerging megacities in Nigeria and DR Congo could present special challenges for the control of NTDs. In the setting of extreme poverty, rapid urbanization and population growth can be expected to outstrip basic infrastructures related to water, sanitation, and hygiene (WASH) and food security [19] such that high levels of NTD transmission might be sustained.
As we head towards 2050, the global health community will need to respond to the continued emergence of NTDs and malaria in DR Congo and Nigeria. Of particular relevance might be the impact of current approaches to malaria control that rely on antimalarial drugs and bednets or for NTDs dependent on preventive chemotherapy, which might not be able to keep up with the intense pressures associated with large populations affected by sustained disease transmission. In the projected megacities of DR Congo and Nigeria, new biotechnologies, including genetically modified mosquitoes and antimalaria or anthelmintic vaccines for hookworm, schistosomiasis, and onchocerciasis might find important new uses [10,20]. Vaccinating against the syndemic anemias might be particularly important and could include multivalent vaccines that simultaneously target malaria, hookworm, and schistosomiasis [21], as well as vaccines to prevent arbovirus infections, viral hemorrhagic fevers, and bacterial diarrheal infections, among other emerging viral and bacterial diseases.
We can already project that DR Congo and Nigeria, especially their emerging megacities, will become new epicenters of the NTDs. Now is the time to embark on long-term strategies for disease control, including the prioritization of the new biotechnologies that will be needed.