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Research Article
Strong negative covariation between toxoplasmosis and CoVID-19 at a global scale: a spurious indirect effect?
Łukasz Jankowiak
Institute of Biology, University of Szczecin, Wąska 13, 71-412, Szczecin, Poland
Corresponding Author
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Coronaviruses may exert severely negative effects on the mortality and morbidity of birds and mammals including humans and domestic animals. Most recently CoVID-19 has infected over 2,360,000 humans and killed more than 165,000. Susceptibility to this disease appears to differ markedly across different societies but the factors underlying this variability are not known. Given that toxoplasmosis exerts both direct and immune-mediated antiviral effects, we hypothesize a negative covariation between toxoplasmosis and measures of the Covid-19 pandemic across countries. We obtained aged-adjusted toxoplasmosis prevalence of pregnant women from the literature. Since the differences in the CoVID-19 morbidity and mortality may depend on the different timing of the epidemics in each country, we applied a standard measure, i.e. the date of first documented CoVID-19 in each country as a proxy of susceptibility, with a statistical control for population size effects. Using these two indices, we show a highly significant negative co-variation between the two pandemics across 86 countries. Then, considering that the wealth of nations often co-varies with the prevalence of diseases, we introduced Gross Domestic Product per capita into our model. The prevalence of toxoplasmosis co-varies negatively, while the date of first CoVID-19 cases co-varies positively with GDP across countries. Further, to control for the strong spatial autocorrelation among countries, we carried out a Spatial Structure Analyses of the relationships between the date of first COVID-19, prevalence of toxoplasmosis, and GDP. Results of this analysis did not confirm a direct causal relationship between toxoplasmosis and susceptibility to the CoVID-19 pandemics. As far as an analysis of observational data let us to suggest, it appears that the interaction between CoVID-19 and toxoplasmosis is mediated by GDP and spatial effects. This prompts the question whether the formerly known covariation between BCG vaccination and CoVID-19 might have also emerged as a spurious indirect effect.
Keywords
BCG vaccination, GDP, ecology of CoVID-19, toxoplasmosis
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This preprint is under consideration at a Nature Portfolio Journal. A preprint is a preliminary version of a manuscript that has not completed peer review at a journal. Research Square does not conduct peer review prior to posting preprints. The posting of a preprint on this server should not be interpreted as an endorsement of its validity or suitability for dissemination as established information or for guiding clinical practice.
Nature journals have partnered with Research Square to offer In Review, a journal-integrated preprint deposition service.
Research Article
Strong negative covariation between toxoplasmosis and CoVID-19 at a global scale: a spurious indirect effect?
Łukasz Jankowiak
Institute of Biology, University of Szczecin, Wąska 13, 71-412, Szczecin, Poland
Corresponding Author
Badges
Prescreen
This manuscript passed our Prescreen assessment
Complete author information
Appropriate declaration statements
Potential risks to human health
Prescreen
Peer Review Timeline
CURRENT STATUS: Under Review
Version 1
Posted 13 May, 2020
Metrics
Comments: 0
PDF Downloads: ...
HTML Views: ...
Subject Areas
Epidemiology
License:
This work is licensed under a CC BY 4.0 License. Read Full License
Coronaviruses may exert severely negative effects on the mortality and morbidity of birds and mammals including humans and domestic animals. Most recently CoVID-19 has infected over 2,360,000 humans and killed more than 165,000. Susceptibility to this disease appears to differ markedly across different societies but the factors underlying this variability are not known. Given that toxoplasmosis exerts both direct and immune-mediated antiviral effects, we hypothesize a negative covariation between toxoplasmosis and measures of the Covid-19 pandemic across countries. We obtained aged-adjusted toxoplasmosis prevalence of pregnant women from the literature. Since the differences in the CoVID-19 morbidity and mortality may depend on the different timing of the epidemics in each country, we applied a standard measure, i.e. the date of first documented CoVID-19 in each country as a proxy of susceptibility, with a statistical control for population size effects. Using these two indices, we show a highly significant negative co-variation between the two pandemics across 86 countries. Then, considering that the wealth of nations often co-varies with the prevalence of diseases, we introduced Gross Domestic Product per capita into our model. The prevalence of toxoplasmosis co-varies negatively, while the date of first CoVID-19 cases co-varies positively with GDP across countries. Further, to control for the strong spatial autocorrelation among countries, we carried out a Spatial Structure Analyses of the relationships between the date of first COVID-19, prevalence of toxoplasmosis, and GDP. Results of this analysis did not confirm a direct causal relationship between toxoplasmosis and susceptibility to the CoVID-19 pandemics. As far as an analysis of observational data let us to suggest, it appears that the interaction between CoVID-19 and toxoplasmosis is mediated by GDP and spatial effects. This prompts the question whether the formerly known covariation between BCG vaccination and CoVID-19 might have also emerged as a spurious indirect effect.
Figure 1
Figure 2
Figure 3
Figure 4