Infectious Diseases Associated with Exposure to Pollutants in a Local Population from Mexico

Abstract

Agriculture is one of the primary activities in the municipality of Acatzingo, Puebla, Mexico. Agricultural fields are affected by the indiscriminate use of pesticides and hydrocarbon spills, which expose inhabitants to the development of infectious diseases. In the present study, we assessed the likelihood of developing infectious diseases associated with environmental contamination (pesticides and hydrocarbons) in various areas of the municipality of Acatzingo, Puebla, Mexico. A questionnaire was applied to 425 people in four areas of two locations divided according to exposure to hydrocarbons and pesticides. We conducted a binomial analysis using a binary logistic regression model, and the odds ratio (OR) was calculated at p ≤ 0.05. The development of infectious diseases is significantly associated with the geographical zone (p = 0.001). The population of Acatzingo de Hidalgo had a higher predicted probability (54.8%) of developing infections. Zone 3, which is exposed to hydrocarbons, had twice the probability of contracting infections (OR = 1.833, p = 0.093). Factors such as tobacco or alcohol consumption, gender, and age did not influence the development of infectious diseases. However, minors, businesspeople, and individuals with chronic degenerative diseases were more likely to contract infectious diseases. Therefore, it is crucial to implement control and regulation in managing pesticides and hydrocarbon spills to mitigate environmental contamination and the associated risks to human health.

1. Introduction

Ecosystems undergo changes due to habitat loss, introduction of invasive species, presence of pathogens, accumulation of persistent pollutants, climate change, and other factors [1,2]. Continuous exposure to pollutants can lead to abnormalities in cell replication, which organisms typically resolve under normal conditions [3]. Different biomarkers have been reported, such as biometrics, histochemical, biochemical assays (catalase activity, glutathione reductase activity, glutathione peroxidase, cholinesterase activity, lactate dehydrogenase activity, and alanine aminotransferase) and genotoxic are tools that determine toxic damage in invertebrate organisms (mollusks) and aquatic vertebrates (fish) caused by organic and inorganic contaminants [4].

The well-being of the human population exposed to various contaminants resulting from anthropogenic activities has become a growing concern in recent years. Contaminants like organochlorine compounds, polycyclic aromatic hydrocarbons (PAHs), and heavy metals adversely affect the immune response, rendering individuals more susceptible to infectious diseases [5,6,7]. In this sense, polychlorinated biphenyls (PCBs) have immunotoxic effects, causing thymus atrophy, impacting the immune response, and having carcinogenic properties alongside PAHs [6].

Agriculture plays a significant role in Mexico, contributing 2.3% to the Gross Domestic Product (GDP) [8]. Acatzingo, Puebla, Mexico, located in the southwest, has a population of 63,743 thousand inhabitants, with 30.48% engaged in agriculture, primarily focusing on prickly pear crops, nopalitos, grain corn, beans, pumpkin, carrot, green tomato, lettuce, cabbage, and broccoli [9,10,11]. Agricultural fields in this area are impacted by the excessive use of pesticides and hydrocarbon spills, as pipelines transporting gasoline, diesel, crude oil, and fuel oil run beneath the producers’ plots [12].

Commonly used pesticides by the region’s producers include organophosphates such as chlorpyrifos, chlorpyrifos ethyl, and malathion; carbamates like methomyl and oxamyl; pyrethroids (lambda cyalothrin); and imides (imidacloprid). These belong to toxicological categories 1b, II, III, and IV, according to the World Health Organization (WHO) [13,14].

Reported hydrocarbon spills from the Acatzingo area amounted to 110.16 billion barrels in agricultural soils during the 2018–2021 period [15]. Continuous exposure to diverse contaminants (heavy metals, metalloids, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls, among others) present in contaminated soils increases the risk of absorption by plants, animals, and humans [16]. Elevated levels of these contaminants can trigger infectious processes. Direct and indirect contact with soil contaminants can damage cell membranes, allowing toxic compounds to enter, triggering an immune system response, and inflammation in response to pathogens [6,17].

Identifying risk factors for developing infectious processes is crucial, especially given that 9.8% (95% CI = 9.0, 10.8) of the Mexican population over 20 years of age is obese or overweight. Additionally, many individuals suffer from chronic degenerative diseases such as diabetes mellitus (12.2%; 95% CI = 11.4, 13.2) and high blood pressure (9.1%; 95% CI = 8.3, 10.0), which compromise their health [18]. Hence, increasing evidence suggests that environmental exposure should be considered a potential risk factor. In this study, we evaluated the probability of developing an infectious disease associated with environmental contamination (pesticides and hydrocarbons) in various areas of the municipality of Acatzingo, Puebla, Mexico.

2. Materials and Methods

2.1. Study Area

The municipality of Acatzingo, Puebla, Mexico, is situated in the central part of the State of Puebla, with a latitude ranging from 18°56′48″ N to 19°06′18″ N and a longitude between 97°49′54″ W and 92°34′18″. The elevation varies between 2000 and 2700 m above sea level. It shares borders with Nopalucan and Soltepec to the north, Los Reyes de Juárez, San Salvador Huixcolotla, Quecholac to the south, Felipe Angeles to the east, and Tepeaca to the west. Acatzingo has a population of 63,743 inhabitants, accounting for 0.97% of the total population of the State of Puebla. For this study, two localities were selected: (A) Acatzingo de Hidalgo and (B) Progreso de Juárez, based on population size and agricultural activity [10].

2.2. Sample Size

Informed consent was obtained from all subjects involved in the study for the application of interviews and handling of personal data.

The study participants consisted of residents of the municipality of Acatzingo, Puebla, Mexico. To determine the sample size, a simple random sampling design was used, considering a two-sided alpha (d) of 0.05, a normal distribution (Z) of 1.96, and a coefficient of variability (CV) of 0.8. The sample size (n) was calculated using the formula recommended by Santoyo et al. [19] in Equation (1):

n = (NZ² × CV²)/(((N − 1)d²) + (Z² × CV²))

(1)

where

• N = Represents the total number of producers;
• Z = Normal distribution;
• CV = Coefficient of variability;
• d = Bilateral alpha;
• n = Sample size.

A semi-structured questionnaire focusing on exposure to contaminants and sociodemographic characteristics was administered to 425 individuals. This data collection aimed to obtain general information and assess the probability of developing infectious diseases associated with exposure to hydrocarbons and pesticides in four geographic zones located in two areas: Acatzingo de Hidalgo and Progreso de Juárez. This sample size was deemed sufficient to detect sample effect sizes of approximately two-thirds of the standard deviation.

The selection of study zones and participant recruitment was primarily based on the conditions of exposure to hydrocarbons due to the presence of pipelines traversing agricultural areas and households and exposure to pesticides in the vicinity of agricultural plots and field activities.

In the locality of Acatzingo de Hidalgo (A), different colonies were selected, constituting three geographical areas: Zone 1 (exposure to pesticides) included El Trebol, Tetela, Maravillas, San Antonio, and El Calvario; Zone 2 (exposure to hydrocarbons and pesticides) comprised San Jerónimo Tamariz, El Capulín, Los Corralitos, La Nueva Concepción, Tres Horas, and San Gabriel; and Zone 3 (exposure to hydrocarbons) included Nuevo Guadalupe. The locality of Progreso de Juárez (B) was designated as Zone 4 (exposure to pesticides) (Figure 1).

Respondents were randomly selected at each selected site. Each zone was selected with a homogeneous population size of around 80 to 91 per site; however, in Zone 1, the population size increased due to the very low incidence of infectious diseases.

Two selection criteria were used; the variables used for grouping were zones (Zone 1, Zone 2, Zone 3, and Zone 4), sex (women and men), occupation (farmer, businessman, housewife, retiree, student, and minors), infectious diseases (once a month or none); and the variables used for stratification were chronic degenerative diseases (type II diabetes mellitus, high blood pressure, breast cancer, leukemia, or none), alcohol consumer (2 times a week, once a week, or no alcohol), smoker (more than 6 cigarettes/week, 1–5 cigarettes/week, or no smoking), and age.

2.3. Statistical Analysis

The response rate was 100%, as none of the included inhabitants in the sample declined to participate after providing their consent. A descriptive analysis was employed to determine central tendencies, dispersion, and associations of factors (means, frequencies, and proportions) concerning sociodemographic characteristics, including age, sex, occupation, tobacco and alcohol consumption, infectious diseases, and chronic degenerative diseases (diabetes mellitus II, arterial hypertension, breast cancer, and leukemia). A chi-square test (X²) was used to assess the goodness-of-fit and independence of factors (X^2. _Pearson) among the studied zones. Additionally, a Pearson correlation analysis of parametric data from the study was conducted at a significance level of p ≤ 0.05.

Finally, a binomial analysis was performed using a binary logistic regression model to predict the development of infections based on predictive variables, including study zones, age, sex, occupation, tobacco consumption, alcohol consumption, and chronic degenerative diseases in the population of Acatzingo, Puebla, Mexico. The odds ratio (Exp B) was calculated, representing the association between the outcome and explanatory variables in the multivariate risk coefficient for infections. Statistical associations were considered significant at a 95% confidence interval (CI) and values of p ≤ 0.05. All calculations were carried out using the IBM SPSS Statistics version 17 statistical package for Windows.

3. Results

3.1. Comparison of Sociodemographic Characteristics

Sociodemographic characteristics across the different study zones, Zones 1, 2, and 3 in the locality of Acatzingo de Hidalgo and Zone 4 in the locality of Progreso de Juárez, were compared. The study group was significantly represented (p = 0.044) by individuals aged between 0 and 29 years (60%), with a smaller proportion (10.1%) comprising adults over 60 years old across all four study zones. The gender distribution was equal, with 58.1% females and 41.9% males, and the predominant occupations were students (47.3%), housewives (24.2%), and farmers (19.3%). Tobacco and alcohol use were low (10.1%) in the population, with significant differences observed among the studied zones (

Table 1. Social and health indicators in studies sites.

Variables	Category	Zone 1		Zone 2		Zone 3		Zone 4		p-Value
		n = 169		n = 91		n = 80		n = 85
		Frequency	%	Frequency	%	Frequency	%	Frequency	%
Age	0–29 years	103	60.9	54	59.3	57	71.3	41	48.2	0.044 *
	30–59 years	49	29.0	27	29.7	21	26.3	30	35.3
	>60 years	17	10.1	10	11.0	2	2.5	14	16.5
Sex	Women	97	57.4	53	58.2	52	65.0	45	52.9	0.470
	Men	72	42.6	38	41.8	28	35.0	40	47.1
Occupation	Farmer	32	18.9	16	17.6	10	12.5	24	28.2	0.108
	Businessman	7	4.1	6	6.6	5	6.3	7	8.2
	Housewife	39	23.1	25	27.5	15	18.8	24	28.2
	Retired	0	0	2	2.2	2	2.5	2	2.4
	Student	88	52.1	41	45.1	45	56.3	27	31.8
	Minors	3	1.8	1	1.1	3	3.8	1	1.2
Smoker	More than 6 cigarettes/week	0	0	0	0	1	1.3	1	1.2	0.044 *
	1–5 cigarettes/week	12	7.1	10	11.0	4	5.0	15	17.6
	No smoking	157	92.9	81	89.0	75	93.8	69	81.2
Alcohol consumer	2 to 3 times a week	0	0	0	0	1	1.3	1	1.2	0.044 *
	Once a week	12	7.1	10	11.0	4	5.0	15	17.6
	No alcohol	157	92.9	81	89.0	75	93.8	69	81.2
Diseases infections	Once a month	10	5.9	51	56.0	51	63.7	44	51.8	0.001 *
	None	159	94.1	40	44.0	29	36.3	41	48.2
Chronic degenerative	Diabetes mellitus type II	19	11.2	20	22	8	10.0	18	21.2	0.005 *
	Arterial hypertension	13	7.7	2	2.2	1	1.3	1	1.2
	Mom’s cancer	0	0	1	1.1	0	0	2	2.4
	Leukemia	0	0	0	0	0	0	1	1.2
	None	137	81.1	68	74.7	71	88.8	63	74.1

Zone 1: Trebol, Tetela, Maravillas, San Antonio, and El Calvario (exposure to pesticides); Zone 2: San Jerónimo, El Capulín, Corralitos, La Nueva Concepción, Tres Horas, and San Gabriel (exposure to hydrocarbons and pesticides); Zone 3: Nuevo Guadalupe (exposure to hydrocarbons); Zone 4: Progreso de Juárez (exposure to pesticides). n: People. *: significant values of p ≤ 0.05.

).

The presence of infectious diseases caused by bacteria, fungi, and viruses showed highly significant differences (p = 0.001) among the study zones, with high frequencies in Zone 2 (56%, 51/91), Zone 3 (63.7%, 51/80), and Zone 4 (51.8%, 44/85), and a lower frequency in Zone 1 (5.9%, 10/169). Therefore, a total of 156 reported cases were documented. Additionally, significant differences were observed in the presence of chronic degenerative diseases (p = 0.005), with diabetes mellitus type II (15.3%, 65/425) being the most prevalent, followed by arterial hypertension (4.0%, 17/425) in the studied areas (Table 1).

3.2. Correlation Analysis

Based on the analysis of the basic characteristics, it was determined that conditions in the evaluated zones directly or indirectly influence the development of infectious diseases. Correlations were performed between the study zones and the study variables. The test results showed that infectious diseases and chronic degenerative diseases were significantly correlated with zones, age, occupation, tobacco consumption, and alcohol consumption (

Table 2. Correlation analysis of variables for zones of study.

Variables	Zones	Age	Sex	Occupation	Smoker	Alcohol Consumer	Infections	Chronic Degenerative
Zones	1	−0.154 **	0.075	−0.078	−0.076	−0.076	0.265 **	−0.115 *
		(0.001)	(0.122)	(0.108)	(0.118)	(0.118)	(0.001)	(0.018)
Age	−0.154 **	1	0.037	0.570 **	0.200 **	0.200 **	0.108 *
	(0.001)		(0.448)	(0.001)	(0.001)	(0.001)	(0.027)
Sex	0.075	0.037	1	0.222 **	−0.298 **	−0.298 **	0.092	0.090
	(0.122)	(0.448)		(0.001)	(0.001)	(0.001)	(0.057)	(0.063)
Occupation	−0.078	0.570 **	0.222 **	1	0.040	0.040	0.182 **	0.311 **
	(0.108)	(0.001)	(0.001)		(0.410)	(0.410)	(0.001)	(0.001)
Smoker	−0.076	0.200 **	−0.298 **	0.040	1	1.000 **	−0.114 *	0.108 *
	(0.118)	(0.001)	(0.001)	(0.410)		(0.001)	(0.019)	(0.026)
Alcohol consumer	−0.076	0.200 **	−0.298 **	0.040	1.000 **	1	−0.114 *	0.108 *
	(0.118)	(0.001)	(0.001)	(0.410)	(0.001)		(0.019)	(0.026)
Infections	0.265 **	0.108 *	0.092	0.182 **	−0.114 *	−0.114 *	1	0.055
	(0.001)	(0.027)	(0.057)	(0.001)	(0.019)	(0.019)		(0.262)
Chronic degenerative	−0.115 *	0.413 **	0.090	0.311 **	0.108 *	0.108 *	0.055
	(0.018)	(0.001)	(0.063)	(0.001)	(0.026)	(0.026)	(0.262)	1

* The correlation is significant at the 0.05 level. ** The correlation is significant at the 0.01 level. The bilateral significance value is indicated in parentheses.

).

3.3. Binary Logistic Regression

The results of the binary logistic regression are presented in

Table 3. Sociodemographic characteristics favorable for the development of infections in Acatzingo, Puebla, Mexico.

Predictor Variable	1 B	2 Odds Ratio [Exp B]	95% CI		p-Value
			Lower	Upper
Zones					0.001 *
Zone 1	−3.265	0.038	0.016	0.090	0.001 *
Zone 2	0.155	1.167	0.600	2.271	0.648
Zone 3	0.606	1.833	0.904	3.714	0.093
Zone 4	0	1
Sex
Women	−0.270	0.763	0.410	1.421	0.394
Men	0	1
Age					0.051
30–59 years	1.551	4.717	1.358	16.384	0.015 *
>60 years	1.408	4.090	0.886	18.878	0.071
0–29 years	0	1
Occupation					0.045 *
Minors	2.226	9.264	0.481	178.509	0.140
Student	1.285	3.615	0.353	36.990	0.279
Farmer	−0.317	0.729	0.094	5.674	0.762
Housewife	0.911	2.486	0.302	20.466	0.397
Businessman	2.100	8.169	0.677	98.517	0.098
Retired	0	1
Smoker					0.017 *
1–5 cigarettes/week	−1.505	0.222	0.079	0.624	0.004 *
More than 6 cigarettes/week	−0.709	0.492	0.022	11.003	0.655
No smoking	0	1
Alcohol consumer					0.017 *
Once a week	−1.505	0.222	1.602	12.663	0.004 *
2 to 3 times a week	−0.709	0.492	0.091	45.432	0.655
No alcohol	0	1
Diseases Chronic degenerative
Presence	0.997	2.709	1.152	6.368	0.022 *
Absence	0	1

Zone 1: Trebol, Tetela, Maravillas, San Antonio, and El Calvario (exposure to pesticides); Zone 2: San Jerónimo, El Capulín, Corralitos, La Nueva Concepción, Tres Horas, and San Gabriel (exposure to hydrocarbons and pesticides); Zone 3: Nuevo Guadalupe (exposure to hydrocarbons); Zone 4: Progreso de Juárez (exposure to pesticides).-2 Log-likelihood= 372.572. Hosmer and Lomeshow goodness-of-fit test (p = 0.085). ¹ B: coefficient of predictor variable; ² Odds Ratio [Exp B]: multivariate risk coefficient. *: significant values of p ≤ 0.05.

. The binary logistic regression model was statistically significant (p = 0.001; Cox and Snell R² = 35.5%, Nagelkerke R² = 48.5%). A significant association was found between the development of infections, indicating strong explanatory power through risk conditions.

The development of infectious diseases was significantly associated with geographical zone (p = 0.001), occupation (p = 0.045), tobacco consumption (p = 0.017), alcohol consumption (p = 0.017), and chronic degenerative diseases (p = 0.022). However, sex (p = 0.394) and age (p = 0.051) were predictive variables that were not significantly related to the development of infectious diseases in the population of the municipality of Acatzingo, Puebla, Mexico (Table 3). Interestingly, tobacco or alcohol consumption habits did not influence the presence of infectious diseases (OR = 0.222, 95% CI = 0.079–0.624, p = 0.004).

3.4. Probability Forecasting

The population of the locality of Acatzingo Acatzingo de Hidalgo had a higher probability of developing an infectious disease, with Zone 3 having a two times higher probability of infections (OR = 1.833, 95% CI = 0.904–3.714, p = 0.093) compared to the locality of Progreso de Juárez (Zone 4). In the other zones (1 and 2) studied in the locality of Acatzingo de Hidalgo, their geographic location did not influence the risk of infections despite exposure to pesticides and hydrocarbons. Occupation was a significant factor, with minors (unemployed) and businessmen being nine to eight times more likely to contract an infectious disease (OR = 9.264 and 8.169; 95% CI = 0.481–178.509 and 0.677–98.517; p = 0.140 and 0.098) than retired individuals. Sex was not significantly related to the development of infections (p = 0.394). However, individuals with chronic degenerative diseases were twice as likely to develop an infection compared to the healthy population (OR = 2.709, 95% CI = 1.152–6.368, p = 0.022) (Table 3). Tobacco or alcohol consumption habits did not influence the prognosis of infectious diseases in the population from both locations.

The probability forecasting for developing infectious diseases in the total population of Acatzingo, Puebla, Mexico, was 72.5% (167/425) (

Table 4. Probability forecasting in the development of infections with respect to sociodemographic characteristics.

Variables	Variables Characteristics	N (TP = 425)	PFTP	Probability Forecasting
			n	%
Infections	Once a month	156	167	72.5	(0.678 ± 0.122)
Sex	Women	247	101	46.8	(0.724 ± 0.124)
	Men	178	66	25.7	(0.607 ± 0.077)
Age	0–29 years	255	89	34.5	(0.604 ± 0.071)
	30–59 years	127	58	28.3	(0.760 ± 0.116)
	>60 years	43	20	9.8	(0.766 ± 0.106)
Occupation	Minors	8	5	2.4	(0.750 ± 0.063)
	Student	201	64	23.5	(0.572 ± 0.037)
	Farmer	82	18	6.7	(0.583 ± 0.057)
	Housewife	103	57	29.7	(0.814 ± 0.070)
	Businessman	25	18	7.9	(0.683 ± 0.055)
	Retired	6	5	2.3	(0.723 ± 0.054)
Smoker	More than 6 cigarettes/week	2	1	0.4	(0.574 ± 0.000)
	1–5 cigarettes/week	41	1	0.4	(0.568 ± 0.000)
	No smoking	382	165	71.8	(0.679 ± 0.122)
Alcohol consumer	2 to 3 times a week	2	1	0.4	(0.574 ± 0.000)
	Once a week	41	1	0.4	(0.568 ± 0.000)
	No alcohol	382	165	71.8	(0.679 ± 0.122)
Diseases Chronic degenerative	Diabetes mellitus type II	65	40	20.2	(0.786 ± 0.096)
	Arterial hypertension	17	2	1	(0.818 ± 0.009)
	Mom’s cancer	3	2	1	(0.809 ± 0.021)
	Leukemia	1	0	NA
	None	339	123	50.3	(0.638 ± 0.106)

N = total population per predictor variable. TP = total population studied. PFTP: total population forecast probability. The number in parentheses indicates the mean of the probability forecast ± the standard deviation. NA: does not apply.

). This probability varied among the two localities studied, with inhabitants of Acatzingo de Hidalgo presenting a higher probability (54.8%) of developing infectious diseases due to exposure to hydrocarbons and pesticides. In particular, Zone 3, consisting of colonies Nuevo Guadalupe in the locality of Acatzingo de Hidalgo, had the highest probability (31.7%) of developing infectious diseases due to hydrocarbon exposure. Zone 2 had a 23.1% probability of infections, with colonies Tres Horas (7.1%), Corralitos (4.0%), and El Capulin (3.9%) being the most affected due to exposure to hydrocarbons and pesticides. Zone 1 did not present a probability forecast for developing infections, as it was only exposed to pesticides (Figure 2 and Figure 3).

The locality of Progreso de Juárez (Zone 4) had a lower probability of developing infections (17.8%) as its inhabitants were only exposed to pesticides. The population aged 0–29 years (34.5%) and 30–59 years (28.3%) had a greater probability of contracting infections, with women having a risk of 46.8%. Students and housewives had probabilities of 23.5% and 29.7%, respectively. Tobacco or alcohol consumption did not influence the prognosis of infectious diseases, nor did the presence of chronic degenerative diseases (Table 4). Therefore, the development of infectious diseases in the studied zones is primarily associated with their geographical location and environmental contamination (pesticides and hydrocarbons) in the municipality of Acatzingo, Puebla, Mexico.

4. Discussion

Health conditions in Mexico have improved in recent decades. However, 26.5% of the population lacks health services, which puts the development of diseases at risk and is aggravated by the presence of chemical substances in the environment, such as pesticides and hydrocarbons [20]. Agriculture in Mexico depends on the widespread use of insecticides, herbicides, bactericides, and fungicides against pests and diseases to maintain its place in the local, national, and global markets. Pesticide inputs in Mexico are 1.9 kg ha⁻¹ (approx. 43,578.14 ton), in addition to the consumption of fertilizers (2,194,245.49 ton), which have been part of intensive agricultural systems, just like in most of the world [21]. The use, management, and marketing of pesticides in the country are regulated by the Ministry of Health (SS), the Ministry of Labor and Social Welfare (STPS), the Ministry of the Environment and Natural Resources (SEMARNAT), the Ministry of Agriculture and Development Rural (SADER), and the Federal Commission for the Protection against Sanitary Risks [13].

The legislation of these organizations includes Mexican laws and regulations, such as the General Health Law, NOM-232-SSA1-2009, NOM-032-FITO-1995, and NOM-003-STPS-1999, which addresses issues on the management, care, risks, and adverse toxicological effects of pesticides [22,23,24]. Thus, such as the NOM-138-SEMARNAT/SSA1-2012 [25], which is about sampling, quantification techniques, and characterization of hydrocarbons for the remediation of contaminated soils [26]. Unfortunately, social, governmental, and industrial interests work against the implementation of an adequate regulatory framework for the marketing and use of pesticides, as well as the prevention of hydrocarbon spills on agricultural soils in Mexico. Therefore, the development of most diseases is the result of cumulative internal chemical exposure between the environment and an individual’s genes throughout their life, defined as an exposome or exposure phenotype, which influences health [27]. These exposures include the external environment (geographical factors), the specific external environment (uniquely experienced extrinsic factors), and the specific internal environment of an individual (byproducts of the hormonal system, metabolism, microbiome, and immune response, among others) [28].

Agricultural workers who apply pesticides and fertilizers are at risk of respiratory diseases, such as allergic and non-allergic asthma, chronic bronchitis, hypersensitivity pneumonitis, and organic dust toxic syndrome (ODTS), due to exposure to organic gases such as ammonia, nitrogen oxides, and carbon dioxide. Additionally, reduced lung function, wheezing, lung cancer, chronic bronchitis, chronic obstructive pulmonary disease (COPD), cough, rhinitis, asthma, and other respiratory symptoms are observed [29].

In this study, we report a frequency of 156 cases with an incidence rate of 72.5% (167/425) of infectious processes in the population (Table 4). Women (247) have a higher predicted probability of infections (46.8%) compared to men. They are mainly dedicated to the home, which makes this occupation have a probability forecasting of 29.7%. In rural communities in Mexico, dedicating oneself to the home also implies dedicating oneself to field practices, which increases their exposure to contaminants. Additionally, women are living in these zones throughout their lives, which increases their exposure to pollutants.

Environmental pollution leads to an increase in respiratory infections, with associated costs and premature deaths in chronic patients and children [30,31]. Pesticides have been quantified in different parts of Mexico, which constitutes an environmental problem since they are present in soil, water, and aquatic fauna [32]. Organophosphate pesticides (chlorpyrifos and malathion) used by producers in the study areas have been associated with chronic bronchitis and lung cancer [33,34]. These organophosphates increase the production of pro-inflammatory cytokines that cause respiratory problems [35]. Likewise, they also generate damage to the bronchial epithelium that increases infection by respiratory pathogens [36,37]. In this study, the population’s exposure to pesticides is associated with a lower probability of developing infectious respiratory processes, locating geographical Zones 1 and 4 of the municipality of Acatzingo, Puebla, Mexico, with a lower probability of risk (0% and 17.8%). However, hydrocarbon contamination (Zone 3) is where there is a greater probability of risk in the population (31.7%). Gutiérrez-Jara et al. [38] associate pesticide poisoning with the spread of infectious respiratory diseases and mention that the potential impact of the transmission of infectious disease will depend on the genetic susceptibility of the population to the toxic substance, which explains the differences between the zones of our study. Furthermore, in Mexican flower growers, paraoxonase-1 activity and PON1 polymorphisms have been related to chronic exposure to pesticides reported in this study, such as oxamyl, imidacloprid, and abamectin, which contribute to ethnic identification but are not associated with tobacco consumption and alcohol, like our results [39].

There is a greater prevalence of infectious diseases when hydrocarbons are present. This is related to the fact that continuous exposure to petroleum products such as PAH has been documented to increase biomarkers such as resistin, IgE, and interleukin-10 associated with adverse respiratory problems such as asthma and pathogenesis [40,41,42]. The work of Hara et al. [43] has demonstrated the association between exposure to PAHs (as benz[a]anthracene] in the air and respiratory symptoms, such as the prevalence of chronic cough in children and adults. As well as its association with chronic bronchitis (1-hydroxynaphthalene OR: 1.559, 95% CI: 1.271–1.912; 2-hydroxynaphthalene OR: 2.498, 95% CI: 1.524–4.095; 3-hydroxyfluorene OR: 2.752, 95% CI: 2.100–3.608; 2-hydroxyfluorene OR: 3.461, 95% CI: 2.438–4.914; 1-hydroxyphenanthrene OR: 2.442, 95% CI: 1.515–3.937; 1-hydroxypyrene OR: 2.828, 95% CI: 1.728–4.629; 2 and 3-hydroxyphenanthrene OR: 3.690, 95% CI: 2.309–5.896) [44]. In addition, PAH compounds are involved in the pathogenesis of respiratory diseases through the induction of local lung inflammation and reflexes of the autonomic nervous system by receptors in the respiratory tract and cross the epithelial barrier, causing responses in tissues and cells [45]. Zone 3 presented the highest probability of developing infectious diseases due to hydrocarbon spills that have caused small plots of land, less than 0.1 ha, to be abandoned without being restored in accordance with the provisions of the Mexican standard NOM-138-SEMARNAT/SSA1-2012 [25]. Therefore, many sites contaminated with hydrocarbons (68,900 mg kg⁻¹ of diesel) [46] present health risks.

Understanding how pollution affects the immune response against infections would allow the establishment of effective epidemiological strategies, improving clinical treatments and quality of life. The majority of the population (37.33%) dedicated to agriculture in Acatzingo, Puebla, Mexico, corresponds to men and 14.51% to women over 12 years of age [10]. However, the lack of regulation of pesticides (approved list for use, import control, distribution, or disposal) and hydrocarbon spills due to the presence of polyducts increase the risk of infections due to short, medium, and long-term exposure. Our study focuses on the prognosis of developing infectious diseases through non-invasive tests; however, one of the limitations of this study is the lack of ability to correlate the risk of developing chronic degenerative diseases or infections with invasive tests, combined with the idiosyncrasy of the population linked to customs and beliefs.

It is necessary to seek more just and equitable social, political, and economic relations by creating environments where knowledge and personal and collective experience are disseminated to eliminate social inequalities. Specialists in the area should encourage creative outreach programs, such as radio programs, workshops on agricultural plots, and seminars, to expand information to groups of producers and agricultural workers due to the risk of exposure to leaching contaminants in rural communities. For Mexico, it is important to establish adequate control and regulation in the safe management of pesticides and hydrocarbon spills due to the growing disturbance of the agroecosystem and risks to human health.

5. Conclusions

This article documents the probability of developing an infectious disease associated with environmental contamination (pesticides and hydrocarbons) in different zones of the municipality of Acatzingo, Puebla, Mexico. The locality of Acatzingo de Hidalgo had the highest probability of developing infectious diseases, with Zone 3 at the greatest risk because it is exposed to hydrocarbons, followed by Zone 2, which refers to hydrocarbon spills and pesticides.

No studies document the risk of exposure to pesticides and hydrocarbons among farmers or agricultural workers in the population of Acatzingo, Puebla, Mexico, which helps implement safe agricultural practices and create a safer agricultural environment in the locality. Thus, it is important to sensitize this group of workers about the need for regular medical check-ups, management, and use of appropriate protective equipment. This study is the first research that aims to raise awareness among the general population about the growing disturbance of the agroecosystem and risks to human health due to the presence and exposure of pesticides and hydrocarbon spills in the municipality of Acatzingo, Puebla, Mexico.