Tropical Health Matters

Intermittent Preventive Treatment of malaria in pregnancy (IPTp) using sulfadoxine-pyrimethamine (SP) has been a long standing intervention to protect pregnant women and their unborn children from the dangerous effects of malaria in stable transmission settings. Placental malaria deprives the fetus of nutrients leading to low birth weight, still birth and miscarriages. The mother herself suffers anemia and potentially, death.

There had always been a challenge to getting pregnant women to obtain at least two doses of IPTp-SP due to a variety of factors ranging from health system lapses to late antenatal care attendance by mothers. This phenomenon of dropping out of multi-contact interventions is not uncommon and seen equally in programs such as childhood immunization. Therefore when the World Health Organization raised the bar and recommended IPTp starting in the 13th week of pregnancy and monthly thereafter, the challenge of providing three or more doses arose.

The Malaria Indicator Surveys (MIS) and the Demographic and Health Surveys (DHS) are an ideal was to trace the progress of malaria intervention over multiple years. With the release of the preliminary results of 2017 Tanzania MIS it is now possible to track this service from over a decade. The Attached chart, using MIS/DHS reports shows that so far Tanzania has not come near achieving 80% coverage of this indicator. While there had been major increases over recent years, reports of IPTp coverage in 2017 show only 56% of recently pregnant women received at least two doses, and only 26% received three or more.

It should be noted that countries are beginning to stratify their interventions according  to available transmission data. Therefore as noted in the US President’s Malaria Initiative Malaria Operations Plan for 2018, Zanzibar where transmission is low, has stopped IPTp and focuses on prompt and appropriate case management, while the mainland of Tanzania continues with all MIP interventions.  Of interest is the most recent child prevalence map found in the 2017 MIS results that shows other parts of the mainland may also be approaching very low transmission.

Moving forward it will be useful if Tanzania and other endemic countries not only gather epidemiological data to help stratify appropriate interventions (as suggested in the WHO malaria elimination framework), but go further to focus reporting by strata. That said, the health system and community difficulties in achieving high IPTp coverage wherever it is appropriate will remain a challenge if services remain based in static health facilities. Community roles must be explored.

Take away messages by the Press sometimes need a bit of clarification. A recent report in The Citizen (Dar es Salaam) expressed that the author was ‘startled’ to mean from the recent Malaria Indicator Suvey (MIS/DHS 2017) that there is high malaria prevalence in regions that also have high insecticide treated bednet ownership and use, implying that nets might not be effective. Actually the preliminary Key Indicators Report showed the overlap between prevalence and nets but did not actually present statistical analysis comparing the two to show whether actual sleeping under the net is associated with prevalence one way or the other.

The reporter quoted Dr William Kisinza, director and chief researcher at the Amani Research Centre of the National Institute for Medical Research as saying “This shows that mosquito bed-nets aren’t the only solution in addressing malaria in Tanzania,” and while this is true, it should not be construed as meaning nets don’t work. Any national malaria strategy uses ITNs in combination with other interventions to have a comprehensive program, including indoor residual spraying, which is also mentioned in the new article.

Dr Kisinza was also quoted as saying, “In Kigoma and Mtwara, bed-nets are used in fishing. There’s a need for behavioural change, if the problem is to be effectively addressed.” This is a real problem but anecdotal. In order to make a clearer point it would be necessary to test the connection between net ownership and use and do a follow-up study to see if in fact those owning but not sleeping under the nets are practicing alternative net usage.

Actually key findings from the preliminary MIS report include the fact that while 78% of households have one ITN, only 45% have at least one for every two people. Hence it is not surprising that only 55% of children under the age of 5 and 62% of pregnant women reported sleeping under a net. These are important service gaps that must be addressed.  Certainly all countries need to monitor the effectiveness of nets and insecticide resistance.

Analysis of net use and malaria parasitaemia among the children can and should be presented to address the reporter’s questions as well as provide a clue to potential insecticide resistance.

WHO lists the milestones towards validation of elimination beginning with stopping the spread of infection through mass drug administration (MDA), implementing MDA in all endemic areas (100% geographical coverage), reducing infection below a threshold at which transmission is not sustainable in all endemic areas and stop MDA, and finally demonstrating sustained reduction of infection below the threshold no earlier than 4 years after stopping MDA. WHO also encourages countries to alleviate suffering by managing morbidity such as lymphedema and preventing disability.

By 2015 the partners providing PCT achieved a milestone. As WHO reports, “Preventive chemotherapy is achievable, as proven by the increasing numbers of people being reached each year. In 2015, over 1.5 billion treatments were administered to almost 1 billion individuals for at least one of the targeted infections: lymphatic filariasis, onchocerciasis, schistosomiasis soil-transmitted helminthiases and trachoma.

village records of MDA activities

At a low cost – between US$ 0.30 and US$ 0.50 per person treated in most settings – preventive chemotherapy remains the most affordable, cost-effective strategy for controlling and eliminating these diseases.” WHO also explains that to be fully sustainable and to maximize impact, PCT the strategy should be combined and delivered with other interventions, including improving access to safe drinking-water, hygiene, disease management and vector control.

USAID as one of the major NTD partners has spent nearly $700 million since 2006 to build the capacity of 33 endemic countries to plan and implement the MDA strategy for the five PCT diseases. By 2016, “USAID-assisted NTD programs had provided a total of more than 2 billion treatments in the respective countries, representing 935 million persons treated.” Over these years the number of persons living in implementation units (e.g. districts) that no longer require MDA has steadily increased.

Of the 25 countries USAID has supported for LF MDA, “Three had already stopped MDA treatment in 2015 (Togo, Cambodia, and Vietnam), Four were expected to stop MDA in 2017, and 10 more countries by 2020. There were eight countries where the date for stopping treatment was anticipated beyond 2020.” Likewise, “Most countries are on track to reach WHO 2020 elimination goals for trachoma,” and nearly all countries shown anticipate reaching post-MDA surveillance by 2021.

In conclusion, Robollo and Bockarie remind us that, “Interventions against neglected tropical diseases (NTD), including lymphatic filariasis (LF), (were) scaled up dramatically after the signing of the London Declaration (LD) in 2012… but some countries are considered not on track to meet the 2020 target using the recommended preventive chemotherapy and morbidity management strategies.” They believe that LF can be eliminated by 2020 “using cross-sectoral and integrated approaches” that incorporate the synergistic effect of the Sustainable Development Goals related to poverty reduction and water and sanitation.

Testing to see if transmission of lymphatic filariasis has stopped in Burkina Faso

Two things we need to note about the list of 20 diseases that the World Health Organization and partners classify as Neglected Tropical Diseases (NTDs). First, diseases like Rabies, Snakebite/envenoming, and Leprosy, while certainly more common in the tropics now, have in the past been global in distribution. Secondly some of the diseases have not been neglected. Onchocerciasis or river blindness has been the focus of a global partnership since 1975, and transmission in the America’s and much of the Sahel in Africa has been halted. Elimination of Dracunculiasis or Guinea Worm has also been the subject of many World Health Assembly Resolutions, and concerted effort has brought the number of cases down from 3.5 million in 1986 to 30 in 2017.  What is more to the point about these diseases is that they affect neglected people, the poor and vulnerable in remote rural areas or urban slums.

Still when we can compare NTD control programs with the rise of major disease control efforts like the Global Fund to fight AIDS, Tuberculosis and Malaria, the President’s Emergency Program For AIDS Relief, the President’s Malaria Initiative, World Bank Malaria Booster Program, Global A Vaccine Initiative among others, we can see that the global community has been able to focus major financial resources on a few diseases.  Now with the Sustainable Development Goals, that focus expanded from infectious to Non-Communicable Diseases.  It is natural therefore to fear that tropical health problems that are responsible for major loss of life and economic capacity will not be adequately addressed.

A system of rewards helped identify the last cases in many guinea worm endemic countries

Based on the World Health Organization’s 2020 Roadmap on NTDs, the London Declaration on NTDs recognized a “tremendous opportunity to control or eliminate at least 10 of these devastating diseases by the end of the decade” (i.e. by 2020). These include eradication of Guinea worm disease, and elimination by 2020 of lymphatic filariasis (LF), leprosy, sleeping sickness {human African trypanosomiasis) and blinding trachoma. In addition drug access programmes should help control by 2020 schistosomiasis, soil-transmitted helminthes (STH), Chagas disease, visceral leishmaniasis and river blindness (onchocerciasis).

Five of the diseases are notable in that they can either be controlled or eliminated through Mass Drug Administration (MDA) using Preventive Chemo-Therapy (PCT). This effort is aided by drug donation programs at the global level and community based MDA at the local level. Ten companies were signatories to the London Declaration and contributed to drug donation programs to achieve MDA. According to WHO,

Preventive chemotherapy is aimed at optimizing the largescale use of safe, single-dose medicines and offers the best means of reducing the extensive morbidity associated with four helminthiases (lymphatic filariasis, onchocerciasis, schistosomiasis and soil-transmitted helminthiases) (6). Additionally, the large-scale administration of azithromycin – a key component of the SAFE strategy for trachoma (that is, lid surgery (S), antibiotics to treat the community pool of infection (A), facial cleanliness (C) and environmental improvement (E)) – is amenable to close coordination and, in future, possibly co-administration with interventions targeted at helminthiases.

Community health workers are the cornerstone of many NTD elimination programs

Targets for the 5 PCT diseases vary. The aim is to eliminate LF and Trachoma by 2020. Although the efforts against onchocerciasis have been running the longest, the refocus from control to elimination meant increasing the geographical scope of intervention, and now elimination may not be feasible until 2025.  With a focus mainly on the school aged and based populations, programs against schistosomiasis and STH talk of control, not elimination, although some endemic countries hope that elimination may be possible if the focus of these programs expands. So far, Togo is the only Sub-Saharan African country to have eliminated LF, and Ghana to have eliminated Trachoma.

Partnerships, funding and drug donations need to be strengthened if more countries are to join the ranks of Togo and Nepal.