National Drug Authority, Abiaz Rwamwiri, Where is Your Science on Tick-Off?
By: Dr. Opira Edward, V.O. Lakang Sub County, Amuru District
The National Drug Authority (NDA) recently accused Pastor Robert Kayanja and claimed to have found three dangerous and potentially carcinogenic chemicals in their organic Tick-Off product. Due to the serious allegations being made, I waited for the report released by the Directorate of Government Analytical Laboratory (Lab Reference Number: PRL 009/2023) to conclude whether the claims could be scientifically justified. Based on my experience and research on each of the chemicals listed by the NDA, Diazinon, Fipronil and Benalaxyl, such claims can not be scientifically supported.
To understand the calculations and scientific research provided, it is important to note that Tick-Off is packaged as 50 grams which is to be diluted by the farmer in 20 liters of water for use on the cow. If a farmer was to use 1 kilogram of the product it would contain 20, 50 gram packets which should be diluted in 400 liters of water.
- Diazinon
This is the first of the three banned chemicals that the NDA raised red flags about. According to their statements ‘Diazinon is a highly concentrated fumigant used to kill bed bugs, bats and termites.’
Diazinon is a pesticide commonly used to control various soil, crops, and livestock pests. It is applied as a spray on plants and livestock, where it interferes with the pest’s nervous system and, as a result, dies.
In terms of any chemical, the concentration of such compounds needs to be considered to understand its effect fully.
The commercially available forms are concentrated at 60%, 50% and 25%, and the intended outdoor concentration is recommended to be a 0.05% solution (Clark, 2007)1.
NDA states they found 0.59 milligrams (mg) per kilogram (kg) of Diazinon in Tick-Off, equivalent to 0.00000295% even before further dilution of 20 liters of water. Once it is diluted, the final concentration is 0.0000001475% which is sprayed on the animal.
Secondly, Diazinon released into the environment is moderately persistent and moderately mobile. A report by the World Health Organization (WHO) investigating pesticide residues in food revealed that Diazinon was found to be mobile in 80% of the 25 soils tested (Diazinon In Pesticide Residues in Food, 2006)2.
Consequently, a joint toxicology evaluation was conducted by the Food and Agriculture Organization of United Nations (FOA) and WHO in 2006 on Diazinon. Two groups of 15 male and female rats were given single doses of Diazinon to test its neurotoxic effects. The findings concluded that up to a 600mg dosage of Diazinon had no lethal neurotoxic effect (Pesticide Residues in Food, 2006)3. This study aids in proving that the quantity of Diazinon in Tick-Off is so insignificant that it can not by any means kill ticks.
A report published in 2008 by the Agency of Toxic Substances and Disease Registry concluded that in plants and animals, “Diazinon is rapidly broken down by most animals that eat it and [are] not likely to build up to high or dangerous levels in animals or plants that you may eat” (Centers for Disease Control and Prevention, 2015)4.
The levels of Diazonan found in Tick-Off were at 0.0000001475%. This is a trace amount and is significantly too low to have any pharmacological activity on animals. So the question is, why would someone intentionally labor to put less than 1mg to kill ticks?- Fipronil
The second accusation by the NDA stated that ‘Fipronil; [is] a spray banned for food producing animals because of long withdrawal period due to the potential risks it could have on human health.”
According to the NDA register, as of February 2022, Fipronil is an authorized active ingredient in PESTIGON (FIPRONIL 100MG), an approved drug for pesticide control Reg No; NDA/MAL/VDP/1594.
Fipronil was found by NDA at a concentration of 0.56mg/kg in Tick-Off. Once diluted in 20 liters of water this gives 0.0000000014% as the final concentration amount applied to the cow. This is different from the active concentrations for most Fipronil formulations for tick control or spot-on treatments, as well as sprays and collars.
This is illustrated by a study published in the Journal of Veterinary Pharmacology and Therapeutics that inspected the effectiveness of Fipronil spot-on treatments for regulating ticks on dogs. It was discovered that Fipronil’s spot-on treatment at a concentration of 9.7% was highly effective in killing and repelling ticks for up to four weeks after application (Dryden et al., 2006)5.
Another study published in the Journal of Medical Entomology investigated the effectiveness of Fipronil spray’s chemical component in subsiding ticks. The study in question found that the spray, with a concentration of 0.25%, was highly influential in killing ticks for up to four weeks after application (Dryden et al., 2000)6.
Fipronil is already a registered drug by NDA, and available in 100mg concentrations. Therefore, what basis does the NDA have to publicly state that Fipronil of these dosages of 0.0000000014% in question can kill ticks or affect the cattle we consume? - Benalaxyl
They stated, “Benalaxyl; a systemic fungicide which is carcinogenic (Cancer causing potentials).”
Benalaxyl is a fungicide and is primarily used for the control of plant diseases caused by oomycete fungi, such as downy mildew and late blight. While Benalaxyl may have some activity against certain pests, including insects and nematodes, it is not typically used as a pesticide for these purposes.
The Public Relations Manager (PRM) for NDA, Mr. Abiaz Rwamwiri stated that ‘science is science.’ He emphasized how the product, Tick-Off, had carcinogenic properties that cause cancer called Benalaxyl.
However, we would like to compare its level of carcinogenicity to that of already approved tick products on the market.
According to the International Agency for Research on Cancer (IARC), some of these acaricides have been classified as a possible human carcinogen for example Chlorfenvinphos – Class Ib (Highly hazardous in ), Amitraz – Class II (Moderately hazardous ) while Benalaxyl was placed in Class III (Slightly hazardous) (The WHO Recommended Classification of Pesticides by Hazard and Guidelines to Classification, 2019)7. Please note that Amitraz and Chlorfenvinphos are approved for use and yet they are listed to be more carcinogenic than the Benalaxyl which was found in Tick-Off.
According to the NDA register, as of February 2022, Amitraz is an authorized active ingredient in MILBITRAZ (12.5% concentration), an approved acaricide Reg No; NDA/MAL/VDP/5696.This drug has been registered since 1998 by the NDA.
According to the NDA register, as of April 2022, Chlorfenvinphos is an authorized active ingredient in DUODIP (50.5% concentration), an approved acaricide Reg No; NDA/MAL/VDP/2881 (Made in UK).
This drug has been approved since 2013 by the NDA.
Secondly, NDA’s report states that Tick-Off has Benalaxyl at a 0.38mg/kg concentration. Once diluted in 20 liters of water the calculation gives 0.00000000095% as the final concentration applied on the cow.
This is not comparable to the concentration required for effective pharmacological impact of Benalaxyl.
That being said, some studies have investigated the potential use of Benalaxyl for controlling specific pests. For example, a study published in the Journal of Pest Science investigated the effectiveness of Benalaxyl in controlling the pine wood nematode, a destructive pest of pine trees. The study found that Benalaxyl applied at a concentration of 50 mg/L effectively reduced the population of pine wood nematodes in the soil (Zhao et al., 2015)8.
Another study published in the Journal of Economic Entomology investigated the effectiveness of Benalaxyl for controlling the common bed bug. The study found that Benalaxyl applied at a concentration of 0.5% was not effective in killing bed bugs or reducing their reproduction (Gondhalekar et al., 2015)9.
So here we are again. How can a concentration of less than 0.00000000095% which was found in Tick-Off, kill ticks, pests, or cause cancer? The amount is so minute that it begs the question of why someone would labor to put it in. The concentrations found are too low to have any significant pharmacological effect on ticks.
In conclusion, the scientific report released by the Directorate of Government Analytical Laboratory (Lab Reference number: PRL 009/2023) does not support the claims and statements made since the concentrations found to be present in Tick-Off are far too low to have the type of effect they were alleged.
The only plausible explanation for the presence of these compounds in the product are the existing chemical contaminants that could be present in our environment.
Ironically, some of these chemicals presented by the NDA are available in much higher concentrations in their approved products today. What are the maximum residual levels presented by NDA for each chemical?
So the questions remain. Were the claims by NDA scientifically based or were they based on a stereotype? Can a concentration of less than 1mg of each compound found in Tick-Off, kill ticks, harm animals, or cause cancer? Are these contaminants already in our environment? And to what extent have we been exposed?
1 Zoe Clarke. Diazinon, The Comprehensive Pharmacology Reference, 2007 Pages 1-4.
2 Diazinon. In Pesticide Residues in Food 2006: Toxicological Evaluations. Geneva, Switzerland: World Health Organization.
3 Food and Agriculture Organization of United Nations and World Health Organization, ‘Pesticide residues in food evaluation, part II Toxicology,’ (2006)
http://apps.who.int/iris/bitstream/10665/43822/1/9789241665223_eng.pdf .
4 Centers for Disease Control and Prevention. (2015, March 12). Public Health Statement for Diazinon. Centers for Disease Control and Prevention. Retrieved
February 17, 2023, from https://wwwn.cdc.gov/TSP/PHS/PHS.aspx?phsid=511&toxid=90
5 Dryden, M. W., Payne, P. A., Smith, V., & Kobuszewski, D. (2006). Efficacy of fipronil spot-on against Amblyomma americanum ticks on dogs. Journal of
Veterinary Pharmacology and Therapeutics, 29(5), 481-483.
6 Dryden, M. W., Payne, P. A., Smith, V., & McTier, T. L. (2000). Comparative speed of kill of selamectin, imidacloprid, and fipronil.
7 World Health Organisation, ‘The Who recommended Classification of Pesticides by Hazard and Guidelines to Classification’, (2019) edn.
8 Zhao, B. G., Cui, J. J., Wang, L., Sun, J. H., & Wang, Z. Y. (2015). Control of pine wood nematode with benalaxyl. Journal of Pest Science,
88(2), 357-364.
9 Gondhalekar, A. D., Nguyen, D., & Potter, M. F. (2015). Evaluation of benalaxyl as a novel insecticide for the control of the common bed bug (Hemiptera:
Cimicidae). Journal of Economic Entomology, 108(3), 1382-1391.