One Health - Policy

A determinant by another name is a problem that must be overcome
Many of the determinants involved in the spread of malaria can be controlled by policy. For example, in areas of Africa where malaria  transmission is unstable (seasonal transmission, low intensity, low immunity among the population, affecting all ages), irrigation patterns affect transmission by affecting (increasing) the number of vectors available at a particular location. Mosquitoes breed well in the water logged soil of rice fields, increasing malaria transmission, although the very purpose of irrigation is to increase food productivity. (Ijumba, 2001) The authors have elegantly called this the 'paddy paradox'. Issues like this are at the very core of the dilemma of achieving all the goals of the One Health Initiative. Because all life is linked in an intricate network, a policy that affects one area inevitably affects another, in a veritable 'circle of life'.

Collaborative efforts and critical areas
One of the Manhattan principles on 'One World, One Health' really caught my eye. It states that "Forming collaborative relationships among governments, local people, and the private and  public (i.e. non-profit) sectors" will "meet the challenges of global health and biodiversity conservation." (CDC,2004). To discuss the need for collaboration is great, but the only thing that will sustain the collaboration is (mandatory) policy that will hold collaborators to their promises.

In a manner similar to the one adopted for HPAI (UNDG,2008)., a coordinated global response policy for malaria must focus on critical areas that include :
a. Preventing a epidemic by controlling malaria transmission and preparing for future epidemics by improving malaria surveillance.
b. Rapidly detecting the disease, treating it and preventing its sustained spread from the index case to others

c. Ensuring that all essential services are continually available in  the event of an outbreak

Whose responsibility is it anyway?

Policies must be put in place for the things discussed above. But, who is responsible for drafting such policies? Will these policies form a basis for laws that could be legislated by different governments? Will the local government that holds executive powers enforce such laws created by a Legislature? Will such laws/policies be upheld by local branches of the Judiciary? Or will the policies only be convention among the involved parties?

For such diseases that have a marked impact on both veterinary and medical fields (like psittacosis, cysticercosis etc), the approach that was taken in the reading for the week in New South Wales (Adamson, 2011) works really well. There can be effective collaboration between vets and physicians for prevention and preparedness, detection , analysis and response. However, it should not escape our notice that malaria is not listed as a notifiable disease by both the human and animal sectors, because many still strictly consider it an obligate human-mosquito pathogen.

With malaria caused by Plasmodium knowlesi however the NSW setup would work perfectly with physicians and wildlife experts filling in their expertise. This framework can be effective in P.knowlesi endemic areas , not so much in others because of differences in the niche occupied by the other Plasmodia.

Stakeholders in the One Health theory

Physicians, who are at the top of the 'health care access pyramid', should work together with researchers, epidemiologists and other stake holders (governmental and nongovernmental) . One example of a non governmental stake holder is the Bill and Melinda Gates Foundation, who support R&D financially by funding research grants (2 billion USD so far) for drug development, diagnostics, vector control methods and vaccines. They are partners with organizations such as the Global fund to Fight AIDS, tuberculosis and Malaria, Roll back Malaria, PATH Malaria Vaccine Initiative, Medicines for Malaria Venture, Malaria No more and Nothing but Nets. Such broad partnerships lay a broad resource network that can well be used to eradicate malaria soon. Although these private investors work on their own time frame and donate money for research, at the present time, there are no laws/ policies according to which they are expected to act. 

This must be rectified and policy frameworks established to moderate everyone's role, without infringing on anyone's freedom to help, because financial gifts cannot be demanded. 

The following pyramid from the Maternal and Child Health Program of the US Dept of Health and Human Services shows the essential features that must be covered by One Health policies for the eradication and management of disease. They can be adopted for malaria. 

(MCH,2013)

References :

1. Adamson S, Marich A, Roth I. One Health in NSW: coordination of human and animal health sector management of zoonoses of public health significance. N S W Public Health Bull 2011;22:105-112.

2. Ijumba JN, Lindsay SW. Impact of irrigation on malaria in Africa: paddies paradox. Med Vet Entomol 2001;15:1-11.

3. "Bill & Melinda Gates Foundation." Malaria. Gates Foundation, Seattle, 2013. Web. 18 Nov. 2013.

4. "MCH Programs Overview." MCH Programs Overview. Washington, 2013. Web. 19 Nov. 2013.

5. "The Manhattan Principles." cdc.gov. CDC, Atlanta, 2004. Web. 19 Nov. 2013.

6. "Contributing to One World, One Health.*" Undg.org. United Nation Development Group, 2008. Web. 19 Nov. 2013.

One Health - Sociology

The sociology of the one heath concept for malaria is built around human social behavior in the context of the disease's zoonotic nature. Of the five species of Plasmodium that can infect man (P.malariae, P.ovale, P.falciparum, P.vivax and P. knowlesi), P.knowlesi is a natural pathogen of long tailed and pig tailed macaques in South East Asia and hence considered a zoonosis. (CDC, 2013).  There are numerous reports of the other Plasmodium species arising in the great apes and engulfing an ecological niche created by the movement of humans.

(Singh, 2013)

 Although wild macaques are the original hosts of P.knowlesi, increased human depredations in forest areas has led to human infections. Some scientists theorize that in such an ecological mosaic such as the one that exists in SouthEast Asia, an increase in human interference could force a pathogenic species such as P.knowlesi to switch to humans as its preferred host. (Lee et al.,2011)

Since P.knowlesi multiplies every 24 hrs, cases of infection progress rapidly, often being fatal. The parasite resembles P.malariae (more benign) and is misdiagnosed as such, when diagnosis is based on microscopy. (Cox-Singh et al., 2008) Visitors entering endemic zones are at the highest risks.

 Spread of the disease is influenced by many cultural factors as well. Due to population booms, much more of the forest land has been cleared for agricultural use, driving people and their animals to the edges of forests. People living in such close proximity to the jungle tend to enter it to forage for food, to gather firewood etc, where they encounter the infected mosquitoes.

There are two transmission cycles that ought to be addressed : (1) between macaques and (2) between humans and macaques. The latter occurs in the ecological mosaic where a vector that can bite both primates exists, which can transmit the parasite (Singh,2013; Thrusfield, 2007). Studies of this sort have involved entomologists, landscape epidemiologists, veterinarians etc. The conclusion that was reached was that the disease is transmitted to humans by mosquitoes that normally feed on animals and that human to human transmission does not seem to occur with the same vectors. It is exceedingly interesting to note that no urban outbreaks of P.knowlesi has occurred.

Management of such a zoonotic pathogen requires coordinated, consistent action from health professionals, scientists and the government, which is the basis of One Health. Further epidemiological studies are warranted. These must look at infection rates, describe intrinsic and extrinsic determinants,  notify nosogenic territories, predict persistence and patterns of the disease. Surveillance must be undertaken by governmental agencies and health organizations. Trips into deep jungles by tourists, naturalists intent on discovering new species, military personnel undergoing jungle training and others must be kept to a minimum.

References :

1. Cox-Singh J, Davis TM, Lee KS, et al. Plasmodium knowlesi malaria in humans is widely distributed and potentially life threatening. Clin Infect Dis2008;46:165-171.

2. Lee KS, Divis PC, Zakaria SK, et al. Plasmodium knowlesi: reservoir hosts and tracking the emergence in humans and macaques. PLoS Pathog2011;7:e1002015.

3. Singh B, Daneshvar C. Human infections and detection of Plasmodium knowlesi. Clin Microbiol Rev 2013;26:165-184.

4. Thrusfield, M. V. "7 : The Ecology of Disease." Veterinary Epidemiology. 3rd ed. N.p.: Blackwell, 2007. 116-36. Print.

5.  Day MJ. One health: the importance of companion animal vector-borne diseases. Parasit Vectors 2011;4:49.

6. http://www.cdc.gov/malaria/about/biology/parasites.html