Polio & The Poisoning of America

Before DDT was introduced in the 1940s, lead arsenate was widely used as a pesticide. It was originally introduced in the United States in 1892, to control gypsy moth.

Massachusetts was the first state to manufacture and begin spraying lead arsenate.

The first small outbreak of polio (26 cases) occurred the following year, in 1893 [1].

Also in Massachusetts.

Boston, Massachusetts actually, which happened to be downstream of where the lead arsenate was being manufactured by Merrimack Chemical Corporation (later bought by Monsanto) in Woburn.

(By the end of the century, Merrimack Chemical Corporation was the biggest manufacturer of lead arsenate in the US. It is estimated that 13 tonnes of arsenic made it’s way into the Aberjona River and Mystic Lakes, which were then public water supplies, during the decades that lead arsenate was being manufactured in Woburn) [2].

Arsenic still contaminates the watershed area downstream of Woburn today, and even decades after production had ceased, rates of childhood leukemia in Woburn were 4-fold higher than the national average [3].

The following year, 1894, an even bigger outbreak occurred just over the state border in Rutland County, Vermont – now officially recognised as America’s first polio epidemic.

Nearly all cases occurred in the Otter Creek Valley, a fertile valley nestled between two mountain ranges, and surrounded by agricultural industries. It was noted that numerous horses, dogs and fowls had also died with symptoms of paralysis, (yet polio is said to only affect humans), and some victims died suffering strange rashes and convulsions (symptoms of poisoning) [4].

Strangely, convulsions were often reported in relation to poliomyelitis, with many doctors confirming that the disease did not seem to be contagious, often seeming to affect only one child in the household, and put it down to “abnormal atmospheric conditions” [5].

There had been numerous isolated cases of ‘infantile paralysis’ for decades, and was originally blamed on teething, because of its propensity to strike suddenly when a child was teething. It may seem odd to us now, to blame teething for paralysis and convulsions, but teething used to be a dangerous business! For example, in 18th century France, one half of all infant deaths were attributed to teething. In 19th century England, 12% of all deaths under 4yrs of age were recorded as teething [6].

What made teething dangerous? The teething powders used to soothe fussing and fractious infants contained mercury [7]. Unfortunately, the connection between mercury and ‘teething deaths’ wasn’t made until the 1940’s, and only after some observant doctors noted the similarities between arsenic and mercury poisoning [8].

It wasn’t just mercurial teething powders that made teething fraught with danger. Opiates, such as laudanum were commonly used to sedate irritable babies and dull the pain of teething, and many cases of lethal intoxication occurred [9].

With the advent of arsenical pesticides, however, clusters of young paralysis victims became more and more common, especially during the summer and autumn months (when the fruits sprayed with arsenic were being eaten, and children were swimming in creeks and waterholes contaminated by pesticide run-off).

As the codling and gypsy moths developed resistance, heavier applications of lead arsenate were required – up to 5 or 6 applications per season. It was not until the 1920’s that researchers realized pesticide residues were not removed by washing or rubbing – about two-thirds of the residue remained on the fruit [10].

By 1929, almost 30 million pounds of calcium or lead arsenate were being sprayed every year, onto the fields and orchards of America [11].

Arsenic was also being widely used in medicine, during the early 20th century, especially as a treatment for syphilis – some patients were given more than 100 injections of arsenic-containing Tryparsamide (which was developed by the Rockefeller Foundation, and manufactured by Merck) to ‘treat’ advanced syphilis [12].

There were several reports of polio following arsenical injections – one of those occurred in a children’s home in Germany in 1913, where 5 children were diagnosed with polio.  All were being treated for syphilis at the time, via arsenical injections [13].

Arsenical injections were also employed to treat yaws – a tropical skin disease. In 1936, a campaign to eradicate yaws in Western Samoa preceded a large polio epidemic. Thirty-six thousand locals were given two or more injections in the buttock. A week after the second injection, the first cases of paralysis appeared – all were in the lower limbs, and all had received arsenical injections. In total, 138 locals suffered paralysis after receiving injections. [14].

When widespread vaccination campaigns began, for diptheria and pertussis, paralysis cases, diagnosed as ‘polio’, also followed [15]. At the time, those vaccines contained mercury as a preservative.

It was not just arsenic or mercury that caused polio symptoms – phosphorus, lead, carbon monoxide and cyanide poisoning were also reported in cases of poliomyelitis.

Lead arsenate finally fell out of favour in the 1940’s and was largely replaced by another poison – DDT. Arsenic-based pesticides weren’t banned until the 1980’s, however, and some ‘modified arsenates’ are still in use today, on cotton crops. It is thought that ground contamination is the cause of elevated levels of arsenic in rice today.

The use of arsenical pesticides in China continued beyond the year 2000, and it is suspected they still continue to use them illegally, hence the presence of arsenic in apple juice imported from China [16]

[1] Putnam JJ, Taylor EW. Is Acute Poliomyelitis Unusually Prevalent This Season? Boston Med Surg J, 1893, 129:509-510.

[2] Aurilio, A.C., Durant, J.L., Hemond, H.F. et al. Sources and distribution of arsenic in the aberjona watershed, eastern Massachusetts. Water Air Soil Pollut, 1995, 81, 265–282.

[3] Durant, John L., et al. Elevated Incidence of Childhood Leukemia in Woburn, Massachusetts: NIEHS Superfund Basic Research Program Searches for Causes. Environmental Health Perspectives, 1995, 103:93–98.

[4] Caverley CS. Infantile Paralysis in Vermont, 1894 – 1922, Published 1924. Available at: https://trove.nla.gov.au/work/15562978/version/209712793.

[5] Queer Epidemic Prevailing Among New York Children, The Meriden Weekly Republican, 17th August 1899.

[6] Malkiel S, Eisenstadt M, Pollak U. Say a Prayer for the Safe Cutting of a Child’s Teeth: The Folklore of Teething, J Paediatrics & Child Health, 2017, 53(12): 1145-1148.

[7] Dally A, The Rise and Fall of Pink Disease, Social History of Medicine, 1997, 10(2):291–304.

[8] Shandley K, Austin DW. Ancestry of pink disease (infantile acrodynia) identified as a risk factor for autism spectrum disorders. J Toxicol Environ Health A. 2011;74(18):1185-1194.

[9] Obladen M. Lethal Lullabies: A History of Opium Use in Infants. Journal of Human Lactation. 2016, 32(1):75-85.

[10] Schooley T, Weaver MJ, Mullins D, et al. The History of Lead Arsenate Use in Apple Production: Comparison of its Impact in Virginia with other States, J Pest Safety Ed, 2008, 10:21-53.

[11] Whorton J. Before Silent Spring: Pesticides and public health in pre-DDT America, Princeton University Press, 1974.

[12] Cormia FE. Tryparsamide in the treatment of syphilis of the central nervous system, Brit J Ven Dis, 1934, 10:99-116.

[13] Wyatt HV. Provocation Poliomyelitis: Neglected Clinical Observations from 1914 to 1950, Bull Hist Med, 1981, 55(4):543-557.

[14] Ibid.

[15] Martin K. Local paralysis in children after injections, Arch Dis Child, 1950, 25:1-14.

[16] Blum D. A is for Arsenic (Pesticides if you please), WIRED Magazine, 19th June, 2012.

The Truth About Vaccines & Other Drugs in Africa

There seems to be a perception in the Western world that African children are dying due to lack of vaccines, but is that actually true? Not exactly.

In many cases, the relentless push for vaccines (usually by outside interests) as a magic fix for disease, has come at the expense of other interventions.

According to UNICEF statistics, Rwanda has 95% – 98% vaccination coverage for diptheria-tetanus-pertussis…yet 37% of children are stunted due to malnutrition. Only 62% have access to proper sanitation [1]

Botswana has 95% children vaccinated with three doses of diptheria-tetanus-pertussis vaccine…but just over half receive Vitamin A supplementation (lauded in the early 1990’s as THE most effective health intervention of all), and only 20% of infants are exclusively breastfed [2].

Malawi is ranked 9th poorest country in the world, with more than half its people living below the poverty line, 9.6 million Malawians (more than half the population) don’t have access to a decent toilet, 5.6 million people (1 in 3) don’t have access to clean water, and 42% of children are stunted [3], yet more than 80% of children are up-to-date with vaccinations…[4].

The Malawi vaccination schedule now includes vaccines for measles, polio, cervical cancer, rotavirus, pneumococcal disease, diphtheria, tetanus, pertussis, hepatitis B, Haemophilus Influenza type B (Hib) [5].

According to UNICEF, almost 90 percent of child deaths from diarrhoeal diseases are directly linked to contaminated water, lack of sanitation, or inadequate hygiene [6], but money that may have been spent on sanitation and procurement of clean water, is spent on rotavirus vaccines instead.

Also, recall that the diptheria-tetanus-pertussis vaccine used in poor African countries is likely the old whole-cell thimerosal-containing vaccine, due to being cheaper than the new acellular vaccine [7].

African countries are increasingly rolling out HPV vaccination campaigns for school-girls. While it’s true that the majority of cervical cancer cases are in developing countries, one can’t help but wonder if HPV vaccination is a wise use of resources, given the more pressing needs in many sub-saharan countries.

In 2011, Merck donated 2 million doses of Gardasil vaccine to Rwanda, and 95% of the nation’s 11-year-old girls were vaccinated. The freebies ran out after three years, at which time Merck offered the vaccine to the Rwandan government at ‘discount prices’. Such donations can have the effect of locking governments into programmes which they later have to fund themselves, at the expense of more pressing issues, and may be more about ‘priming the market’, than charity on the part of the drug company [8-9].

Between 2013 – 2016, 26, 766 young girls in Malawi were given quadrivalent HPV vaccination as part of a pilot project, supported by GAVI – and 2051 girls who participated were under the age of 9 [10].

Vaccination coverage in Tanzania in 2014 for school and out of school girls was estimated at 93 per cent and 92.6 per cent, respectively. The chief Health Minister boasted that, despite “heartbreaking stories of the ill effects of vaccines” online, Tanzania had not even registered one single adverse reaction from the vaccine [11]. Is there an incentive for African governments – hopeful of foreign investment from pharmaceutical companies to downplay risks and reactions, in order to keep up the flow of income?

In December 2012, 500 children in Chad received a new experimental meningitis vaccine, and 38 children were later hospitalized, with 7 of the children flown to Tunisia for specialized treatment. The Chadian government declared their “state of health is not worrying”, but other sources in Chad claimed the children were paralysed [12-13].

In 2008, the Center for Research on Multinational Corporations reported (among others) the case of clinical trials in Uganda between 1997 – 2003, where thousands of women suffered adverse reactions to the drug Nevirapine, and some died – and all of it went unreported, while testing continued [14].  

Supplemental Immunization Activities

In addition to routine childhood vaccines, WHO and other agencies also conduct ‘supplemental immunization activities’, which are mass vaccination campaigns that aim to administer extra doses of vaccines. According to the WHO, there have been “thousands of these supplementary vaccination campaigns” with oral polio vaccine since the 1980’s, with children vaccinated regardless of prior vaccine history. The extra doses were not recorded on the child’s health cards [15].

Extra doses of measles vaccines are also given. A quick look at the Measles and Rubella Initiative Calendar for 2019 shows they plan on supplementally vaccinating more than 100 million people in sub-Saharan Africa this year – in addition to routine vaccinations [16].

Experimental Vaccines

In addition to routine vaccinations and supplementary vaccination, poor African countries are increasingly used to test experimental vaccines because it’s quicker and cheaper and less stringent regulations than western countries “Development cycles can be reduced thanks to the faster recruitment of subjects from a larger pool of patients. The costs of recruiting patients and paying investigators are lower too” [17]

This poses some real ethical problems. I have never been to Africa but I have lived in a developing country, and witnessed first-hand the reverence given to those who are in positions of power, or overseas-trained. People are too embarrassed or intimidated to ask questions of their doctor or report side-effects, as it would seem disrespectful and ‘out of line’ with the societal and cultural hierarchy.

Other developing regions face similar issues. M. Nabeel Ghayur, a pharmacologist who worked in drug development in Pakistan says: “People actually have blind trust in their doctor in South Asia. They have no idea what drug development is, they have no idea what clinical trials are.

He said there was little red tape in those countries, and that people would rarely ask about drug side effects and legal issues” [18].

Starting next month (March, 2019), 750,000 babies in Kenya, Ghana and Malawi will be given a new experimental malaria vaccine. The vaccine Mosquirix will be given to children in four doses- at six, seven, nine and 24 months through an injection on the upper arm [19].

 The Star newspaper in Kenya reported: “Mosquirix, also called RTS,S, was first conceived in the 1980s and has undergone all clinical trials, returning less than optimal results.

The vaccine – made by GSK – is only effective in 30 to 50 per cent of patients, says the WHO.

Its effectiveness diminishes over time and it disappears fastest in children who are most exposed to malarial mosquito bites. However, because no defence against malaria is perfect, the vaccine is being considered in addition to the existing defences” [20].

GlaxoSmithKline and its backers, including Bill and Melinda Gates Foundation, had already spent $565 million on developing the drug, which brought back disappointing results in early testing, and did not meet the expected criteria for a malaria vaccine set out by a WHO-led consortium”, which requires a “protective efficacy of more than 50% against severe disease and death, and last longer than one year.” [21]

In 2017, the Global Task Force on Cholera Control launched a very ambitious set of goals, including 90% reduction in cholera deaths by 2030. Naturally, vaccines feature prominently, namely the oral cholera vaccine. A year later, the ‘largest vaccination drive in history’ took place, with over 2 million people vaccinated for cholera in Zambia, Uganda, Malawi, South Sudan and Nigeria [22].  

As of January 2019, more than 66,000 people in the Democratic Republic of Congo have been vaccinated with Merck’s V920, an experimental Ebola vaccine [23].

A Chinese-made genetically-engineered Ebola vaccine was given to 500 adults in Sierra Leone in 2015, as part of a Phase II trial. The Chinese FDA then approved the vaccine, without any Phase III trials [24].

In 2018, some 20,000 Malawian children were enrolled to receive an experimental typhoid conjugate vaccine [25].

Supplemental Drugs

In addition to routine vaccines, supplemental vaccines and experimental vaccines…many African children (and pregnant women) are also given supplemental drugs – malaria (sulfa) drugs, three times during the first year of life (starting from 10 weeks old), or several times per year during childhood – even if they have no infection [26]. During pregnancy, mothers are given the drugs at least three times during the 2nd and 3rd trimesters – again, even if they have no infection [27].

This is called “intermittent preventive therapy”, and it was promoted aggressively by the Bill and Melinda Gates Foundation, to the tune of at least $28 million dollars, with the establishment of the ‘IPTi Consortium’ [28].

in 2008, a technical advisory group at the World Health Organization (who coincidentally has received more than $2.4 billion in donations from the Bill and Melinda Gates Foundation, since 2000 [29], including a $1.2 million grant in 2006, with the express purpose of ensuring “that the IPTi consortium outcomes are collated, assessed by international experts, and result in a WHO policy recommendation” [30])  failed to recommend the program, due to concerns over safety and efficacy.

The protests from the Gates Foundation and their scientists were so loud and insistent, it prompted WHO malaria chief to write a memorandum (which was later leaked to newspapers) to WHO director, Margaret Chan, saying: “although it was less and less straightforward that the health agency should recommend IPTi, the agency’s objections were met with intense and aggressive opposition from Gates-backed scientists and the foundation…” [31]

Not to be deterred, the Gates Foundation then donated funds to have the Institute of Medicine conduct another review, chaired by a doctor whose work has received at least $50 million in funding from the Gates Foundation [32].

Predictably enough, the IOM review concluded that “an intervention with results of this magnitude is worthy of further investment as part of a public health strategy to decrease morbidity from malaria infections in infants“, although they noted that “time and resources did not allow independent audits of trial conduct, data management, or analysis” [33].

The WHO malaria chief who protested the excessive influence of the Gates Foundation, was later replaced…by a member of the Gates-founded IPTi Consortium (and now Vice-President of Johnson & Johnson pharmaceutical company [34]) and WHO then proceeded to recommend these sulphonamide drugs to infants ( given at the same time as routine vaccines for diptheria-tetanus-pertussis and measles), children and pregnant mothers, despite evidence of increasing drug-resistance in sub-Saharan Africa…

Prior to the IPTp and IPTi programs, pregnant women in malaria-endemic areas of Africa were given weekly doses of chloroquine, until drug resistance and compliance issues made it unfeasible to continue [35].

Other chemical exposures

The use of DDT to control mosquitos in malaria-endemic areas was endorsed by the World Health Organization in 2006, and its use has been increasing ever since. The chemical is sprayed inside homes and buildings – according to a report by the United Nations Environment Program, at least 3952 tonnes of DDT were sprayed in Africa and Asia in 2007 [36].

Agricultural spraying of DDT is common in Africa, especially in West Africa, where mosquitos have developed resistance to it [37].

The vast wealth of precious metals and natural resources in Africa have been both a blessing and curse to its people. Gold and other mining in Africa have produced countless mountains of toxic wastes that pollute the air, soil and water, most notably with uranium, arsenic and lead [38].

Another form of pollution experienced in poorer parts of the world, such as sub-Saharan Africa, is indoor air pollution from cooking over open fires, using wood, charcoal, kerosene or animal dung. The World Health Organization estimates that as many as 3.8 million people die prematurely every year, due to health conditions caused by indoor air pollution, the majority due to pneumonia [39].


[1] UNICEF, Statistics: Rwanda https://data.unicef.org/country/rwa/. Accessed February, 2019

[2] UNICEF Statistics: Botswana, https://data.unicef.org/country/bwa/. Accessed February, 2019.

[3] WaterAid, Facts and Statistics: Malawi, https://www.wateraid.org/mw/facts-and-statistics. Accessed February, 2019.

[4] WHO, WHO and UNICEF Estimates of Vaccine Coverage, 2017 Revision, https://www.who.int/immunization/monitoring_surveillance/data/mwi.pdf, Accessed February, 2019.

[5] GAVI The Vaccine Alliance, Iceland pledges US $1 Million to Immunise Children in Malawi, https://www.gavi.org/library/news/statements/2019/iceland-pledges-usd1-million-to-immunise-children-in-malawi/, Accessed February, 2019.

[6] UNICEF, Press Release, Children Dying Daily Because of Unsafe Water Supplies and Poor Sanitation and Hygiene, New York: UNICEF, 2013.

[7] WHO, Biologicals: Pertussis, https://www.who.int/biologicals/vaccines/pertussis/en/. Accessed February, 2019.

[8] The Guardian, Drug donations are great, but should Big pharma be setting the agenda? https://www.theguardian.com/world/2013/apr/29/drug-company-donations-bigpharma. Accessed September, 2017.

[9] Editorial, Financing HPV vaccination in developing countries, The Lancet, 2011, 377(9777):1544.

[10] Msyamboza KP, et al, Implementation of a human papillomavirus vaccination demonstration project in Malawi: successes and challenges, BMC Public Health series, 2017, 17:599.

[11] AllAfrica, Tanzania: Cancer Vaccination Program Registers Success, https://allafrica.com/stories/201602152199.html, Accessed February, 2019.

[12] MedicalExpress, 38 children hospitalised after meningitis shot in Chad, https://medicalxpress.com/news/2013-01-children-hospitalised-meningitis-shot-chad.html#jCp. Accessed February, 2019][

[13] England C, Minimum of 40 children paralyzed after new meningitis vaccine, VacTruth, https://vactruth.com/2013/01/06/paralyzed-after-meningitis-vaccine/. Accessed February 2019

[14] Kelly S, Testing drugs on the developing world, The Atlantic, 27th February 2013, https://www.theatlantic.com/health/archive/2013/02/testing-drugs-on-the-developing-world/273329/. Accessed February, 2019.]

[15] Helleringer S et al, Supplementary polio immunization activities and prior use of routine immunization services in non-polio-endemic sub-Saharan Africa, Bulletin of the World Health Organization, 2012, https://www.who.int/bulletin/volumes/90/7/11-092494/en/. Accessed February, 2019.

[16] Measles and Rubella Initiative, SIA Schedule, https://measlesrubellainitiative.org/resources/sia-schedule/. Accessed February, 2019.

[17] Edwards M, R & D in Emerging Markets: A new approach for a new era, McKinsey & Company, 2010, https://www.mckinsey.com/industries/pharmaceuticals-and-medical-products/our-insights/r-and-38d-in-emerging-markets-a-new-approach-for-a-new-era. Accessed February, 2019.

[18] Joelving F Many drugs for US kids tested in poor countries, Reuters, 23rd August 2010, https://www.reuters.com/article/us-drug-tests-idUSTRE67M1VO20100823. Accessed February, 2019.

[19] Kulkani P, Malaria Vaccine trials in Africa: Dark saga of outsourced clinical trials continues, Newsclick, March 2018, https://www.newsclick.in/malaria-vaccine-trials-africa-dark-saga-outsourced-clinical-trials-continues, Accessed February 2019.

[20] Muchangi J, Kenyan children to get first malaria vaccine in the world next month, The Star,14th February, 2019, https://www.the-star.co.ke/news/2019/02/14/kenyan-children-to-get-first-malaria-vaccine-in-the-world-next-month_c1894869. Accessed February, 2019.

[21] Kulkani P, Malaria vaccine trials in Africa: Dark saga of outsourced clinical trials continues, Newsclick, 17th March 2018, https://www.newsclick.in/malaria-vaccine-trials-africa-dark-saga-outsourced-clinical-trials-continues. Accessed February, 2019.

[22] UNICEF, Global Task Force on Cholera Control marks a year of progress toward ending cholera worldwide, https://www.unicef.org/press-releases/global-task-force-cholera-control-marks-year-progress-toward-ending-cholera. Accessed February, 2019.

[23] Ward Hackett D, Ebola vaccinations expanding in Central Africa, https://www.precisionvaccinations.com/v920-ebola-vaccine-now-deployed-drc-uganda-and-south-sudan. Accessed February, 2019.

[24] Liu A, China approves domestic Ebola vaccine developed from recent outbreak, FiercePharma, https://www.fiercepharma.com/vaccines/china-approves-self-developed-ebola-vaccine-from-2014-outbreak-virus-type. Accessed February, 2019.

[25] Gordon M, Trial kicks off in Malawi: First child vaccinated with typhoid conjugated vaccine in Africa, http://www.coalitionagainsttyphoid.org/trial-kicks-off-in-malawi-first-child-vaccinated-with-typhoid-conjugate-vaccine-in-africa/. Accessed February, 2019.

[26] WHO, Intermittent Preventive Treatment in Infants, https://www.who.int/malaria/areas/preventive_therapies/infants/en/?fbclid=IwAR1yumPwTyZEqBUzCIlPatU8pafeR9qUbNBYTA-vf8_38iyhvAumqK7xTlE. Accessed February, 2019.

[27] WHO, Intermittent Preventive Treatment during Pregnancy, https://www.who.int/malaria/areas/preventive_therapies/pregnancy/en/. Accessed February, 2019.

[28] Bill and Melinda Gates Foundation, New grants to accelerate malaria research and development, https://www.gatesfoundation.org/Media-Center/Press-Releases/2003/09/Grants-for-Malaria-Research. Accessed February 2019.

[29] Huet N & Paun C, Meet the world’s most powerful doctor: Bill Gates, Politico, 4th May 2017, https://www.politico.eu/article/bill-gates-who-most-powerful-doctor/?fbclid=IwAR1t3JJlmxNRTqcZpgvo4dPAFtrZw5vknQJRd_4gDPaU06emIgnLGUtMl6s. Accessed February, 2019.

[30] Bill and Melinda Gates Foundation, How We Work: Grant, WHO, https://www.gatesfoundation.org/How-We-Work/Quick-Links/Grants-Database/Grants/2006/10/OPP37476. Accessed February, 2019.

[31] McNeil DG, Gates Foundation’s Influence Criticized, New York Times, 16th February 2008, https://www.nytimes.com/2008/02/16/science/16malaria.html?fbclid=IwAR1otqtbJWZ8t4lO-XIVDRfQmasdDlTR5Iy6BkjoCh65fDhCECvTazjIkAI. Accessed February 2019.

[32] VCU School of Medicine, Myron Levin M’67: A pioneer of the modern discipline of vaccinology, https://wp.vcu.edu/somdiscoveries/2017/05/myron-levine-m67-a-pioneer-of-the-modern-discipline-of-vaccinology/. Accessed February, 2019.

[33] [IOM, Committee on the Perspectives on the Role of Intermittent Preventive Treatment for Malaria in Infants, 2008, available at: https://www.who.int/immunization/sage/10_IOM_report_on_IPTi.pdf. Accessed February 2019.

[34] UW Dept of Global Health, Robert Newman, https://globalhealth.washington.edu/faculty/robert-newman. Accessed February 2019.

[35] Heymann DL, Antenatal chloroquine chemoprophylaxis in Malawi: chloroquine resistance, compliance, protective efficacy and cost, Trans R Soc Trop Med Hyg,.1990;84(4):496-8.] [Kayentao K et al, Comparison of Intermittent Preventive Treatment with Chemoprophylaxis for the Prevention of Malaria during Pregnancy in Mali, The Journal of Infectious Diseases, 2005, 191(1):109–116.

 [36] Cone M, Should DDT be used to combat malaria? Scientific American, 4th May 2009, https://www.scientificamerican.com/article/ddt-use-to-combat-malaria/. Accessed February 2019.

[37] WorldWatch, Malaria, Mosquitos and DDT, http://www.worldwatch.org/node/517. Accessed February. 2019.

[38] AlJazeera, Toxic City: The cost of gold-mining in South Africa, https://www.aljazeera.com/programmes/specialseries/2019/01/toxic-city-cost-gold-mining-south-africa-190123160346656.html?ref=hvper.com. Accessed February 2019.

[39] WHO, Household air pollution and health, https://www.who.int/news-room/fact-sheets/detail/household-air-pollution-and-health. Accessed February, 2019.