Читать книгу The Experiment Must Continue - Melissa Graboyes - Страница 19

Modern Narrative

A “REMARKABLE ACHIEVEMENT”?

A Lymphatic Filariasis Elimination, Zanzibar, 2001

World Health Organization workers arrived on the island of Unguja (often called Zanzibar) in the Zanzibar Archipelago off the coast of Tanzania in 2000 to begin work on an ambitious yet straightforward plan: to eliminate the disease lymphatic filariasis (LF). The levels of LF on the island were among the highest on the globe: roughly 15 percent of the entire population was infected; in some villages, nearly 30 percent of the population had microfilariae, indicative of the disease in their blood. The disease would be attacked using precise, modern techniques targeting the parasite inside the human body. If everyone on the island—roughly a million people—took a single pill once a year for five years, a disease that had long plagued the island’s residents could be defeated. Getting one million people to all take a pill on the same day would constitute one of the largest “mass drug administrations” ever attempted anywhere on the globe—and present a daunting set of logistical hurdles. Yet according to the WHO, if more than 75 percent of Zanzibaris took the drugs at the same time and then continued to do so for another four years, LF could be defeated. This would be a clear victory for local and international public health organizations, would save many Zanzibaris from disfigurement through grossly enlarged scrotums, legs, arms, or breasts, and would reap untold economic benefits.

The Zanzibar campaign in 2001 was one part of a larger WHO effort to eradicate LF globally through the newly created Global Programme for the Elimination of Lymphatic Filariasis (GPELF). One early success of the GPELF was to negotiate a donation from the pharmaceutical companies GlaxoSmithKline and Merck & Co., which promised to provide free drugs for as long as was needed.¹ This agreement paved the way for a global strategy that relied on distribution of free yearly treatment in poor countries.

The WHO worked closely with officials in the Zanzibar Ministry of Health to help coordinate the logistically complex campaign. The WHO made clear that, while they were providing technical support and expertise, it was the Zanzibaris who would be responsible for the actual work—and there was a lot of work to be done. The plan described how on a single day—October 27, 2001—nearly every Zanzibari (excluding the pregnant, very young, and very ill) would be given a single pill, which would kill all of the microfilariae existing in their bodies.² Three thousand specially recruited and trained Filariasis Prevention Assistants (FPAs) would each be responsible for visiting fifty households to administer the drugs. Public service announcements, maps with lists of households assigned to each assistant, the distribution of pills to the regions where they would be used, and transportation all had to be coordinated.

The plan was based on the logic of treating every single resident living in an LF-infected region regardless of whether they actually had LF. By treating everyone, there would be no need for testing to identify who actually had microfilariae in their blood, but it would also mean subjecting healthy people to the treatment’s side effects and using far more of the drugs than was strictly needed to treat those actually infected. Five years was determined to be the likely length of time required. The yearly drug treatment would kill all baby worms (microfilariae), which would mean stopping transmission to the mosquito vector, and adult filariae had a maximum life expectancy of five years. When there were neither microfilariae nor adult filariae in the body, the disease would be eliminated.

In addition to the daunting logistics of getting a pill to everyone on the island, there was also the small matter of convincing every Zanzibari that s/he should actually take the pill. A degree of local resistance was assumed, and the FPAs were expected to make two visits to each of their fifty households prior to their final visit, when they would watch everyone swallow the single pill. The first two visits to the households were meant to register everyone living in the house, explain side effects of the drug, and address any concerns, in addition to showing the pills and explaining that each person would need to swallow the drug in the presence of the FPA. The WHO explained how each of the FPAs had been specially trained to address local concerns. Yet, there were many questions that didn’t seem to have satisfactory answers: “Why are the drugs free? Why not test our blood first? Why you, and not a medical doctor? Why lymphatic filariasis and not malaria?” Meanwhile, rumors began to circulate that the free tablets to be handed out were a form of birth control or had “unknown side effects.” Rather than greeting the WHO and Ministry of Health workers with appreciation, residents bluntly told the public health workers, “We don’t need these drugs. Please don’t come here.”³

MAP 3.2. Tanzanian coast. Map by Chris Becker.

When raising doubts about the campaign, residents recounted failed public health schemes from prior decades, particularly the massive failures of the malaria elimination attempt in the 1960s. Beginning in 1954, a WHO-led campaign in Zanzibar had focused on reducing mosquito populations, and successfully cut malaria rates from 7 percent to 1.7 percent.⁴ But, with the island going through dramatic political changes, including a violent coup, the WHO abandoned the project in 1968. Soon after, the disease returned with a vengeance and residents were left to suffer the deadly effects of rebound malaria.⁵ The similarities between the 1960s malaria campaign and the 2000s LF campaign were glaring—at least to many Zanzibaris. As one resident told the WHO, “We don’t want the malaria experience to come back. We are afraid of that. . . . People fear that this [commitment] will not be sustained.”⁶ Noisy criticism of the campaign focused on the perceived links between the government and the public health workers, and directly asked whether government would act in the best interest of citizens. Zanzibaris stated to the FPAs and Ministry of Health employees, “If it is something beneficial to us, you [government workers] would never bring it to us.”⁷ There also remained difficulties in aligning local public health priorities with international funding interests. Although the WHO had decided on a global elimination campaign targeting LF, people were quick to note that LF was not a real concern, and pointedly asked, “Why are you giving us drugs for this when malaria is killing us?”⁸

In retrospect, possibly more jarring than residents’ worries is the health officials’ apparent obliviousness. In the very same report where the WHO reported islanders’ distrust and requests to cancel the campaign, they claimed that the modern filariasis elimination campaign reinforced “Faith in government. Faith in international health campaigns. Faith in medicine.” They also asserted that Zanzibar was an ideal site for the project because previous public health campaigns had “sensitized the population to large-scale public health efforts.”⁹ Such statements evidence the profound disconnect that continues to exist between many public health and medical workers and the larger public. The report goes on to predict that, “if LF is pushed out of the islands, faith will be revived in health initiatives. . . . If it works, it will show the people that the government takes care of their health.”¹⁰ The grand predictions about restored faith in public health institutions and government beg the simple question: What would become of this presumed faith if LF was not eliminated from the islands?

. . .

What actually happened on that October day in 2001 when drugs were first distributed? As would be expected with such a large campaign, problems popped up in the final weeks and days leading up to the mass administration. The donated drugs arrived in Zanzibar only eleven days prior to the planned date. Rather than three thousand FPAs, more than four thousand were eventually needed and hastily trained. Even with the increased number of assistants, most FPAs had to visit sixty to seventy households rather than the planned fifty. Although some people refused to take the drugs, local authorities handled many of the incidents. As one sheha (local official) offered, “Everyone took the tablets except one man. He ran away twice, but I will go back for him.”¹¹ Potentially more problematic, on the actual day for drug distribution there were widespread drug shortages, and administration continued into the following day. The good news was that 76 percent of the total population took the pill: the campaign had succeeded in its goal. As the WHO report summed up, “the people of Zanzibar had made a rational cost/value decision.”¹² Even skeptics could agree that the goal for the first year had been accomplished. If mass drug administration could happen consistently in future years, LF would be eliminated from the island.

Between 2001 and 2007, Zanzibar continued yearly mass administration and distributed more than five million total doses of albendazole and ivermectin to the 1.1 million residents of the island. Over those six years, 70–80 percent of the total Zanzibari population received drugs.¹³ After the fourth year of mass drug administration (MDA), two sentinel sites measured only 1 percent and 0 percent microfilariae prevalence rates; after the fifth round of MDA, both sites had 0 percent prevalence.¹⁴ At that point the program was considered to be in the “terminal phase,” which consisted of maintaining zero transmission.¹⁵ The activities in Zanzibar indicate that it is possible to interrupt transmission and that MDA can be an effective strategy.¹⁶ It remains to be seen whether the parasite densities are low enough in humans (and that introductions of new infections from the mainland are rare enough) for all LF transmission to stop. While Zanzibar has been declared a successful example, claims about successful elimination are notoriously slippery, since the term implies that the disease will be gone permanently. We must wait and hope that this will be the case in Zanzibar.

The WHO Progress Reports for the GPELF remind everyone of the clear path countries must take to attack the disease: begin by mapping the disease foci, undertake mass drug administration for five years, and, after this, a period of surveillance and eventual verification of disease elimination. Official WHO reports and plans make no mention of failures that might jeopardize the global campaign. In fact, quite the opposite sentiment is put forth. The plan remains to fully eradicate LF by 2020 and the claim is that the goal is half accomplished. International publications as early as 2006 were touting the program’s “remarkable achievement.”¹⁷ From some angles the news does look promising: among the fifty-three countries globally that have begun mass drug administration, thirty-seven have already distributed the drugs for five or more years as recommended. In Africa, ten countries have administered at least five years of drugs over 100 percent of their geographic area.¹⁸ Yet, of those thirty-seven countries, only five have moved into the surveillance phase that implies the disease has likely been eliminated.¹⁹ Those five countries—Sri Lanka, the Cook Islands, Tonga, Vanuatu, Niue—account for an amazingly small proportion of the global burden of LF.²⁰ In Africa, the only country that is mentioned as having moved into the surveillance phase is Togo. (Zanzibar is not mentioned as a country that has moved into this phase because it is part of Tanzania, and the remainder of the country has not been nearly as successful as the island of Zanzibar.)²¹ There is something comforting in the linearity implied in these steps—that diseases really can be eliminated by following a simple master plan—but such formulaic prescriptions ignore the many uncertainties that continue to characterize eradication attempts. It remains unknown if five rounds of MDA will actually lead to halted transmission and permanent elimination of LF in most countries, and it is unclear how to keep areas free of LF in the longer run. It also remains largely unacknowledged that the history of past attempts in each place—whether failures of malaria elimination, or successes of other public health programs—will be important in determining how receptive local people are to these internationally backed activities. Although these short-term successes in Zanzibar are important and praiseworthy, it remains to be seen whether the program in Zanzibar actually “represents an excellent model for other countries.”²²