Resurgence of Malaria - A Study

 

Malaria resurgence refers to the situation in which malaria returns to a region after having previously been suppressed through malaria control activities such as distribution of bed-nets or spraying with insecticide.

Resurgence is the result of the fact that there is a certain intrinsic potential for malaria in an area, mathematically described by the basic reproduction number R0.

Although malaria can be reduced from that baseline by implementation of effective control measures, in the absence of active suppression malaria will return to a prevalence level determined by R0.

This intrinsic potential for malaria transmission may evolve slowly as a function of socioeconomic development or environmental change.

Such structural changes may eventually result in sufficiently low potential that active measures are not required to suppress transmission, but the malaria baseline will usually be unaffected by commonly implemented malaria control activities.

About Resurgence:

The concept of resurgence as a return towards a baseline level of malaria is distinct from that of “rebound”, which is used to describe a hypothetical overshoot that could occur in populations that have lost their immunity.

According to the World Health Organisation, there were an estimated 216 million cases of malaria and 655,000 deaths in 2010, with 86% of all cases occurring in children under five years old. Ninety-one percent of malaria deaths occurred in Africa.

Access to effective treatment and prevention, including insecticide-treated mosquito nets and indoor residual spraying, has increased dramatically in recent years, and reported malaria cases were reduced by more than 50% in 43 of the 99 countries with ongoing transmission between 2000 and 2010.

These gains in have been made possible by an increase in international funding for malaria control from only $300 million in 2003 to almost $2 billion in 2009.

However, uncertain economic times have led to expected declines in malaria funding, including the cancelation of the latest funding round from the Global Fund.

Despite these cutbacks, ensuring sufficient and sustained funding for malaria control and continued implementation of key interventions even once the disease is absent or low must be the utmost priority if resurgence of malaria is to be prevented.

Today, the threat of resurgence again looms as constrained global funding and competing priorities threaten the sustainability of successes. Brief increases in malaria incidence in countries including Rwanda and Zambia have raised fears about whether recent gains against malaria can be sustained and extended.

At the same time, it has been suggested that technical problems—such as insecticide resistance and reduced effectiveness of insecticide-treated nets—may complicate continued progress in countries including Kenya and Senegal.

Ensuring that today’s successful malaria programmes learn from history rather than repeat its mistakes requires a careful accounting of what has gone wrong in the past and an understanding of the factors that have driven those failures, whether technical, operational, or financial.

Accordingly, a systematic literature review was conducted to identify all documented malaria resurgence events and the causes to which they have been attributed.

Malaria Resurgence in India- A study:

In 1953, the Indian National Malaria Control Programme (NMCP) was started. Encouraged by the results, and the fact that insecticide resistance in vector species may evolve and become an obstacle, in 1958 a control programme was converted to the National Malaria Eradication Programme (NMEP).

By 1964, malaria was eradicated from 88% of the area and it was in the advanced stage of spraying in the remaining parts. At that time, focal outbreaks that occurred in 1965 and increased in later years, could not be contained due to the shortages of DDT.

As a result, large areas in consolidation and maintenance phases were reverted to the attack phase. Besides, the infrastructure in general health services was not adequate and mature enough to take up surveillance and vigilance.

This produced a large number of secondary cases due to the re-introduction and relapse of malaria. Added to this was the problem of urban malaria, the control of which was the responsibility of local bodies.

Malaria cases increased in towns, and started diffusing to the rural areas, due to inadequate staff and the shortages of malarial larvicidal oil (MLO).

Later, it turned out, that while it was technically feasible to eradicate malaria from 91% of the population, the strategy of indoor spraying of DDT to interrupt transmission did not succeed in 9.0% of the population, despite more than 12–14 years of regular spraying.

During the years of resurgence, there was no research support to the programme, so that technical problems were not properly appreciated, understood and tackled.

The reservoir of parasites that were present throughout the country started multiplying and spreading to newer areas due to the presence of vectors in high densities. Thus malaria resurged and re-established itself even in areas that were at one time freed from the disease.

The analysis of the pattern of malaria resurgence revealed that malaria outbreaks preceded the true problem of insecticide resistance.

It is noteworthy to mention that malaria resurgence occurred in towns where the control measures were non-insecticidal and in regions which were not under the influence of insecticide-resistant vectors.

The study also revealed that resurgence occurred before the introduction of high-yielding varieties programme in the country, and had no relationship to either the cotton or rice growing or intensive agriculture.

“There has been a significant reduction in malaria mortality and morbidity since the Global Fund started in 2002. The number of cases has come down and global death rates have decreased by about 60%.

It’s all incredibly exciting, but in the last two or three years we have reached an inflection point,”. Progress is slowing, and, in some places, the number of cases and deaths are once again starting to rise.

“Malaria is like a coiled spring. You can squeeze it really hard, but if you let go, if populations grow and don’t get access to prevention, or you do not treat it effectively, it can suddenly spring back, and return to baseline rates very quickly. It’s unforgiving,”.

Step Up the Fight Against Malaria:

As international development funding has plateaued, populations have continued to grow, meaning per capita expenditure has gone down, and more resources are needed to continue the fight.

“With current funding levels we might not be able to maintain the progress we have made, and we are nervous that the number of cases and deaths will continue to increase,”.

The World Health Organization estimates malaria control will cost US$6.5 billion a year by 2020, compared to US$2.8 billion in 2015. An increasing global population, however, is not the only reason for this increase.

Mosquitos are becoming resistant to insecticide:

Malaria-carrying mosquitos have developed resistance to insecticides used on bed nets, and human conflict and environmental disaster also take their toll. Recent unrest in Venezuela, for example, led to the collapse of the health care system, and cases have skyrocketed.

“It was close to eliminating malaria, and now there are 1 million cases a year. It shows how a country on the cusp of eliminating the disease can return to a highly deadly prevalence within just a couple of years.”

Conclusion:

The Global Fund’s malaria investments are focused primarily on sub-Saharan Africa where 90% of all cases occur. In these high-burden countries, prevalence can be 40-50%, and as many as 150 in every 1,000 children die before their fifth birthday.

Malaria, Dr. Filler says, is deeply connected to poverty, meaning high-burden areas lack the resources to tackle the problem alone.

“We concentrate the bulk of our resources in those areas, but we also work in the marginal countries so that when they have eliminated the disease, we can move the resources to those that haven’t,” he says, adding the organization worked with research and development partners on projects such as new insecticides.

Ultimately, the fight against malaria is about saving lives and improving quality of life in commu­nities that often do not have a voice, he says.

“We strongly believe that removing malaria from the equation of development can contribute to an upward spiral, to a place where countries can lift themselves out of poverty and sustain their own health programs.”

Written by – Sakshi Chauhan