04 Feb Lessons from Africa: Challenges of the Zika Virus
By Gary Littlejohn
The outbreak of the Zika virus in Central and South America, across some 23 countries, has caught international health agencies by surprise. It has also shown up in recent months in Cape Verde, so it has returned to Africa after circling the globe eastwards in less than 70 years. It was first identified in Uganda in 1947, and was thought to be benign, with many people showing no symptoms, or a few symptoms that were manageable, and tended to last for about 10 days. Some of the symptoms are reminiscent of dengue fever, but are less severe. This similarity of symptoms has also affected the accuracy of diagnoses among doctors who have not encountered it before, and has probably delayed organised responses to some extent. There is no treatment for it, and any vaccine would take at least three years to develop, which is far slower than the current pace of events. This implies that public hygiene and preventative health measures will be the most appropriate health policy response in the immediate future.
It spread from Africa to Pakistan and Indonesia in the 1970s, and from there to Micronesia in the Pacific Ocean, where it was detected in 2007 on the island of Yap. From there it has spread to the Americas, with Colombia and Brazil reported to be particularly affected. In the last 9 months or so, it has clearly spread rapidly among populations that have not had time to build up any immunity. It is now being seen as constituting a threat that is at least as great as that of the recent Ebola outbreak in West Africa, which itself is not completely over yet. Consequently it will stretch the resources not only of national health agencies in each country, but also of international health agencies such as the World Health Organisation (WHO) and international medical and health charities.
So far the virus has spread across the tropics, but in the case of the Americas, it could easily spread into the USA as people travel north, or mosquitoes travel on their own. Health experts are on record as saying that only the (basically cold) countries of Chile and Canada will escape infection in the Americas, because the mosquitoes cannot survive there.
It has now become clear that the disease can be spread by other mosquitoes, in addition to Aedes aegypti, the original vector. These additional species are also daytime biting mosquitoes. It can also be spread by sexual transmission, and from mother to foetus. It is claimed that the rate of sexual transmission is very low. Though I cannot see how one can be sure of that, since most adults (perhaps 80 per cent) are unaware of symptoms, apart from the occasional rash. In many of these countries, the health services are extremely unlikely to have picked up evidence of sexually transmitted cases, so I think that one must suspend judgement about the rate of sexual transmission until more data is available. In addition, one must also reserve judgement about the length of time that the virus stays in the body. The fact that the symptoms are over in about ten days does not mean that the virus is gone. Indeed the mention of the possibility of transmission at birth as well as through the placenta suggests that it can survive much longer. It is not clear if anyone knows at this stage whether or not it is like Chicken Pox, in the sense that the latter never leaves the body and can cause Shingles decades later. I have seen no evidence on this issue.
In Brazil, a health prevention project was already under way to evaluate the effectiveness of releasing genetically modified (GM) mosquitoes into the environment as a means of reducing the incidence of dengue fever (a notorious haemorrhagic fever). With the advent of the Zika virus, this approach is now being used to try to limit the prevalence of the new health hazard. Yet, the release of GM mosquitoes to combat the Zika virus may be counter-productive. Inevitably such information is rather limited given the state of medical understanding at this early stage of the outbreak in Central and South America. The problem with the use of GM mosquitoes is claimed to be that Brazil uses a lot of tetracycline in its animal feed, which allegedly affects the timing of when the fatal gene in the GM mosquitoes becomes active, thereby rendering GM mosquitoes less effective. Apparently Brazil has a higher use of tetracycline for this purpose than almost any other country. In addition, the El Nino event of 2015 created conditions for lots more pools of stagnant water in Brazil and elsewhere.
The preventive measures being considered by health professionals include the use of DDT to eliminate the affected species of mosquitoes, despite the known adverse consequences for the environment. This may prove to be unavoidable, while attempting to minimise the negative environmental impact, if other public health measures prove ineffective. There is ample evidence that public health education often has little impact. Yet Mozambique in the period immediately after independence can be seen as an example of effective health education.
In Mozambique, the approach to malaria was basically to persuade people to ‘drain the swamp’ with a campaign of digging latrines, getting rid of standing water, and Dutch aid to build a large ditch in Maputo (now with a highway on either side known as the Via Rapida). The latter dramatically reduced the incidence of malaria in Maputo. The clearance of standing water can be very low tech, if one secures widespread voluntary support. In recent days I watched a Brazilian women complaining to camera about large pools of standing water resulting from a house demolition. There was enough earth above the water on the site to level the site to bury the water so that mosquitoes would not breed there. This sort of self-help action no longer happens in Mozambique, but it is worth recalling the experience as an example of community participation in public hygiene.
To indicate the context, it should be borne in mind that before he left for Algeria for military training prior to joining the armed struggle for Mozambican independence, Samora Machel had been a male nurse. After independence, he retained a strong interest in public health and would make long speeches on the radio encouraging people to improve their hygienic practices. Mozambique manufactured its own transistor radios and these were readily available in rural areas. (Agricultural advice was also disseminated by this and other means.) The Ministry of Health was one of the first in the world to publish and use a generic list of pharmaceutical drugs, which were much cheaper but as effective as commercial brands. Medical students had to live in rural areas with their teachers as part of their training, so that they understood the health problems of the rural poor and what measures could be taken to deal with them. There was also a series of public campaigns, including an ongoing one to encourage villagers to dig latrines 11 metres deep to reduce infection risks. During the war against Renamo, the population was encouraged to live in Economic Priority Areas (EPAs) which were chosen for soil fertility and because they were located next to the coast, so that they could be defended more readily against Renamo attacks, which could thereby only come from further inland. At this time of denser population groupings, hygiene was even more important and it was during this time that a record number of latrines were dug.
This ability to achieve ‘popular mobilisation’ was based on a tradition that had been established (with less than total success) after independence. It included a tradition of jornadas (voluntary additional work days) that most commonly took place during July, when the actividades de Julho were encouraged. Yet jornadas could be organised at other times by any group of volunteers who felt that something needed to be done. To give an unusual example, foreigners who had come to Mozambique out of solidarity were known as cooperantes. The cooperantes from the UK were organised into a group known as MAGIC (Mozambique Angola Guinea-Bissau Information Centre) through which most of them had been recruited to Mozambique. On discovering that the East Timor independence movement was in difficulties, MAGIC organised a jornada during which they donated two water pumps to irrigate some agricultural land occupied by FRETILIN (Frente de Libertação de Timor Leste Independente) and planted 8,000 cabbages in a single day. This basically helped FRETILIN to feed its members in Mozambique and to grow as more members arrived from Portugal.
It is my view it is this kind of ‘voluntary community buy-in’ that should be fostered in Latin American countries, as well as in Africa. In the case of Rio de Janeiro, there are open sewers quite near the Olympic Stadium. Apart from encouraging people to form voluntary groups to fill in puddles with earth and otherwise deal with standing water where mosquitoes can breed, it seems to me that dry reed beds of varying sizes (as circumstances require) would also help treat raw sewage and eliminate standing water. Dry reed beds work because the reeds allow oxygen into the roots, where aerobic bacteria digest almost any form of pollution including raw sewage and of course the reeds absorb water to grow. The important thing is to design the underlying ground structure with materials such as gravel and clay to ensure that the underlying slope of the reed bed slows down that water flow to the point at which the bacteria have time to digest the pollution. Companies capable of such design work have existed for decades, but since they would be unable to operate on the scale required by this health emergency a different approach to reed bed construction is needed.
Given the extensive risk to the poorest sections of the population, this would need to be done by a system of cascade training (involving training of trainers) that has already been devised for India (though not actually implemented, regrettably). There are universities or colleges in Brazil and elsewhere that could be used as training centres for trainers in the construction of dry reed beds. This would require initial emergency funding from national governments, international aid agencies, or cooperation with the charities specialising in the provision of clean water. The reed beds could then be constructed by trained local volunteer groups.
There is a fear among experts of the prospect that a mutated virus associated with microcephaly returns to Africa. Given the proximity of Cape Verde to mainland Africa that is indeed a possibility, as is transmission to Portugal, owing to historical connections affecting possible human travel. In that case, Africa would find that the Zika virus had returned in a much more harmful form from its travel round the world.
Gary Littlejohn is the author of Secret Stockpiles: A review of disarmament efforts in Mozambique, Working Paper 21, Small Arms Survey, Geneva, October 2015. He was also Briefings and Debates editor of the Review of African Political Economy from 2010 to 2015.