Infectious Diseases in the Global Health era

Health

Definition by the World Health Organization (WHO) in 1948 is widely described as “a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity” [1]
Physical health:
- Capable of allostasis (when confronted with stress, a healthy organism is able to maintain an adapted equilibrium and reduce the potential of harm by a protective response) [2]
- If this coping strategy is not successful, damage remains, which eventually results in illness
Mental health:
- Antonovsky: capacity to cope, recover from strong psychological stress and prevent post-traumatic stress orders [3]
- Includes the comprehending, managing, and knowing the meaningfulness of a difficult situation
- A better capability to adapt to and to manage situations and yourself, can respond in an improved subjective well-being and may result in a positive interaction between mind and body
Social health [4]:
- Covers many dimensions in the social domain
- Capacity to fulfill their potential and obligations
- Managing life in an independent way
- Participating in social activities including work
- Could be described by a dynamic balance between opportunities and limitations in the community

Eight Millennium Development Goals (MDGs) [5]

Manifested by the United Nations and its member states in 2000
Improvements, for example in world poverty and hunger, primary education, gender equality, child mortality and fighting diseases
Range until 2015
Could be seen as improvements in health as defined by the WHO
But along many stakeholders, some topics were not adequately represented or poorly covered
Key arguments for the stakeholders [6]:
- Considerable geographical overlap of NTDs
- The commonness of co-infections related to shared risk factors
- Poverty-driven and –promoting characteristics
- Potential synergies in fighting them

Neglected Tropical Diseases

In MDG 6, so called “other diseases” were concealing a cluster of diseases that became known as Neglected tropical diseases (NTDs).
NTDs are directly associated with:
- Low income, inadequate sanitation and missing coverage of basic health services [7]
The WHO has listed so far 17 diseases under its NTD programme [7]:
- Dengue fever, chikungunya fever, rabies, trachoma, buruli ulcer (i.e., Mycobacterium ulcerans infection), leprosy (Mycobacterium leprae infection), chagas disease (American trypanosomiasis), human African trypanosomiasis (sleeping sickness), leishmaniasis, cysticercosis, dracunculiasis (guinea-worm disease), echinococcosis, food-borne trematode infections, lymphatic filariasis, onchocerciasis (river blindness), schistosomiasis (bilharziasis), and soil transmitted helminthiases
These diseases are called “neglected” because they are not prioritised in terms of control and funding compared to the “big three” HIV/AIDS, malaria and tuberculosis; considering the mortality, one NTD alone kills more young children every year than these “big three” combined [8]
Since there were little resources devoted to NTDs (related to their burden), many foundations and organizations were founded and existing ones launching programmes as preventive mass drug administrations
Some examples are:
- Foundation for Innovative Diagnostics (FIND) in 2003
- Drugs for Neglected Diseases Initiative (DNDi) in 2003
- WHO NTD department was established in 2005
- United States Agency for International Development (USAID) launched its NTD programs in 2006
Prevention of NTDs through:
- Sanitation
- Safe water
- Hygiene related programs
- WHO formulated a Global Strategy on ‘Water, Sanitation and Hygiene for accelerating and sustaining progress on Neglected Tropical Diseases’ (WASH).

Sustainable Development Goals (SDGs) [8] (2015)

Successor of the MDGs within a timeline until 2030
The NTDs are listed under 3.3., which can be seen as breakthrough.
Nutrition is an important factor as well.
- Unger et al. [9] observed and compared different nutritional states of children under 5 years in Niger, Malawi and Tanzania; even these countries have a high rate of poverty, the nutritional status differs widely [10]
- Epidemiological data have shown that malnutrition increases the risk of infectious morbidity and mortality in childhood [11]
- The relationship between infection and malnutrition is complex (Fig. 1).

The blue arrows symbolize the cycle of immunity, infectious disease risk and needs of nutrition
The black cycle represents the antimicrobial resistance (AMR) risk
Grey boxes indicate required interventions at the specific situations to reduce malnutrition and risks of diseases and AMR
Malnutrition is on both sides of the coin, it is the cause and the consequence of infectious disease episodes
Promoting optimal nutrition for the integrity and engaging on malnutrition can improve on both disease and AMR rate by using less amounts of antibiotics [9]

Figure 1: The complex relation between infection, disease, antimicrobial resistance (AMR) and nutrition [adapted from Schaible U. E., Kaufmann S.H., Malnutrition and infection: complex mechanism and global impacts, PLoS Med. 2007]

An appropriation for reducing the risk of diseases and AMR could be:

Offer nutritional education
Provide targeted interventions for malnourished children (including the treatment)
Provide guidance, hygiene and promotion in recognition of symptoms
Diagnose and treat infections right (e.g. using least amount of antibiotics)

These points can improve mothers or carers of children in reducing the incidence of infectious diseases (higher immunization), decrease time of recovery and lower the risk of re-infection.