Exposure to Coccidioides spp. and silent infection in Sonora, Mexico: A cross-sectional serological and environmental analysis

Abstract

Coccidioidomycosis is an endemic fungal disease in arid regions of the Americas, yet population-level exposure in Mexico remains poorly defined. This study aimed to evaluate the frequency and spatial distribution of asymptomatic individuals with anti-Coccidioides IgG antibodies residing in different municipalities of Sonora, Mexico, and to evaluate the environmental factors associated with the seropositivity presented. A cross-sectional serosurvey was conducted using 534 serum samples collected from 15 laboratories at different municipalities of Sonora. Anti-Coccidioides IgG antibodies were detected using a commercial enzyme immunoassay. Seroprevalence was analyzed by demographic characteristics, and to evaluate whether environmental conditions differed between municipalities with and without evidence of Coccidioides spp. exposure, mean values of 19 bioclimatic variables were calculated. Overall, IgG seropositivity was 7.3%, with an additional 15% showing indeterminate results. Higher seropositivity was observed among young adults and in individuals that reported no travel to endemic regions in the United States of America. The Mann–Whitney U test identified a significant difference only for temperature seasonality (BIO4) between municipalities with and without seropositive individuals; this difference remained significant after correction for multiple comparisons. These findings provide serological evidence of exposure to Coccidioides spp. in nine municipalities of Sonora. The indeterminate percentage of 15% in an area considered endemic is striking and given that the chosen test is designed for diagnosis, lower cut-off points should be considered for serological surveillance or prevalence studies in asymptomatic populations to provide more information on the hidden burden of coccidioidomycosis in endemic regions.

Introduction

Coccidioidomycosis (CM) is a fungal infection caused by Coccidioides immitis and Coccidioides posadasii; human cases of the disease come from regions characterized by a dry climate of North, Central, and South America.¹, ² Although the epidemiology of CM has been extensively studied in the southwestern United States of America (USA), the burden and geographic distribution of infection across much of Latin America remain insufficiently defined, and the disease is frequently underrecognized and underreported.³ In Mexico, CM is not a notifiable disease; unofficially, the national hospital discharge registry of the Ministry of Health showed 426 cases of CM in the period 2016–2025 and 192 deaths (2016–2024) [http://www.dgis.salud.gob.mx/contenidos/basesdedatos/BD_Cubos_gobmx.html]. These available clinical data mention Sonora as the Mexican state with the highest number of hospital discharges with a CM diagnosis, making Sonora a key region for investigating population exposure to Coccidioides and deepening the epidemiology of the mycosis it causes.⁴ Unfortunately, there are no studies that have identified the predominant species in Sonora, and nor virulence studies in situ, due to a lack of infrastructure, among the collected Coccidioides isolates. CM exhibits a wide spectrum of clinical presentations, ranging from asymptomatic infection to severe disease involving the lungs and other organs.⁵ It is estimated that a considerable proportion of infections are asymptomatic or present with mild symptoms and therefore remain undiagnosed; however, exposed individuals can develop measurable humoral and cellular immune responses against Coccidioides spp. In Mexico, the prevalence of these immunological markers and their relationship to the frequency of the disease in apparently endemic communities remains poorly documented, representing a significant gap in current epidemiological knowledge.^6–9

Historically, intradermal skin tests with coccidioidin or spherulin (cocci-ST) (T-cell-mediated delayed hypersensitivity response) have been used in clinical and epidemiological settings to determine the host’s immune status and disease prognosis, as well as to identify previous infection and population-level exposure.¹⁰, ¹¹ Studies conducted in Sonora have shown that cocci-ST positivity varies widely depending on the population evaluated, with reported rates ranging from 12% to 90%.^12–15 More recent findings indicate that individuals with positive cocci-ST results frequently develop indurations >15 mm, suggesting a robust and occasionally uncomfortable inflammatory response that may limit the acceptability of this method in field settings.^13–15 Serological assays provide an attractive alternative for exposure assessment because they are minimally invasive, scalable, and suitable for large population studies. Detection of anti-Coccidioides IgG antibodies may offer useful evidence of prior or ongoing exposure in endemic areas. A direct validation or equivalence comparison between ST (skin test) vs. enzyme immunoassay (EIA), is not possible because the ST measures delayed-type cellular immunity and, the EIA used in this study detects circulating anti-Coccidioides IgG antibodies, so skin test positivity and IgG seropositivity should not be interpreted as interchangeable markers. Data regarding the frequency of anti-Coccidioides antibodies among asymptomatic populations in Mexico are scarce.

In addition to host-related factors, the environmental ecology of Coccidioides spp. is influenced by climatic and geographic variables such as temperature, rainfall patterns, seasonality, elevation, and land characteristics.³, ⁴ Previous ecological niche and species distribution modeling studies have used bioclimatic variables, topography, GIS-based approaches, and algorithms such as GARP and Maxent to identify environmentally suitable areas for Coccidioides spp. in Mexico and adjoining regions of the Mexico–USA border.¹⁶, ¹⁷ These studies have shown that bioclimatic information can help characterize potential habitat suitability and guide targeted environmental sampling for the fungus. Therefore, integrating serological findings with geospatial environmental analyses may improve understanding of the ecological conditions associated with exposure risk and fungal circulation.

This study aimed to determine among asymptomatic individuals the frequency of IgG antibodies against Coccidioides spp. in different municipalities of Sonora, Mexico, using a commercial EIA. The results obtained from this seroprevalence survey allowed us to examine the relationship between seropositivity, bioclimatic and topographic variables in order to identify some factors that enable the development and dispersal of the fungus in nature.

Materials and methods

A cross-sectional, retrospective study was conducted using residual serum specimens obtained through non-probabilistic convenience sampling from 15 clinical laboratories located in nine municipalities in Sonora. The specimens were collected between October 2023 and January 2024. A total of 534 serum specimens from individuals residing in Sonora were included.

Participants were individuals attending participating laboratories for routine blood testing who reported no respiratory symptoms at the time of sampling and no known history of immunodeficiency. They provided demographic information, including age, gender, residence, and travel history to Arizona or California, USA. Informed consent was obtained for the use of blood specimens and anonymized epidemiological data for research purposes. This study protocol was reviewed and approved by the research and bioethics committees of the Medicine School at UNAM under the reference number FM/DI/049/2021. Serum specimens were aliquoted and transported from Sonora to Mexico City under a cold chain at 4°C for EIA testing.

For Coccidioides antibody (Ab) detection, we used the Clarus Coccidioides Ab enzyme immunoassay (CAb EIA) (Product reference CAB102, IMMY®, Norman, OK, USA), according to the manufacturer’s instructions. For the present study, only IgG results were analyzed. Test values were categorized using the manufacturer´s interpretative criteria as follow: positive (≥1.5 CF EIA units), indeterminate (≥1 to < 1.5 CF EIA units), or negative (<1 CF EIA units). According to the supplier’s instructions, indeterminate means that antibodies concentration against Coccidioides is not high enough to be considered positive, but also not low enough to be classified as negative.

Descriptive statistic was used to summarize demographic characteristics (categorical variables: sex, age group, municipality of residence, and travel history to the USA) and serological results. Continuous variables were expressed as medians and ranges, and categorical variables as frequencies and percentages. Associations between seropositivity and demographic variables were evaluated using the chi-square (χ²) test and Fisher’s exact test, as appropriate. Statistical analyses were performed using SPSS® (SPSS, Chicago, IL, USA) and R software (version 4.0.2).

To explore whether municipalities with serological evidence of Coccidioides spp. exposure differed in their environmental profiles from those without detected exposure, municipalities were grouped according to the presence of at least one seropositive sample: municipalities with one or more seropositive individuals (Mun_pos = 1) and municipalities with no seropositive individuals among the sampled participants (Mun_pos = 0). Mean values of 19 bioclimatic variables were derived for each municipal urban center using zonal statistics from a recent meteorological dataset^.18 These variables included annual mean temperature (BIO1), mean diurnal range (BIO2), isothermality (BIO3), temperature seasonality (BIO4), maximum temperature of the warmest month (BIO5), minimum temperature of the coldest month (BIO6), temperature annual range (BIO7), mean temperature of the wettest quarter (BIO8), mean temperature of the driest quarter (BIO9), mean temperature of the warmest quarter (BIO10), mean temperature of the coldest quarter (BIO11), annual precipitation (BIO12), precipitation of the wettest month (BIO13), precipitation of the driest month (BIO14), precipitation seasonality (BIO15), precipitation of the wettest quarter (BIO16), precipitation of the driest quarter (BIO17), precipitation of the warmest quarter (BIO18), and precipitation of the coldest quarter (BIO19).

Specifically, mean values were calculated by overlaying urban settlement polygons with raster layers of each environmental variable. Topographic variables, including elevation (DEM) and slope, were obtained using the same zonal approach from national elevation data provided by INEGI (https://www.inegi.org.mx/app/geo2/elevacionesmex/). Given the relatively small sample size and the unequal number of municipalities in each group (n = 9 and n = 21, respectively), as well as the non-normal distribution of several environmental variables, differences between groups were assessed using the non-parametric Mann–Whitney U test, a rank-based test for comparing two independent groups that does not require normally distributed data and can be applied to groups with unequal sample sizes^.19 Because multiple environmental variables were evaluated independently, P-values were adjusted for multiple comparisons using the Benjamini–Hochberg false discovery rate (FDR) procedure. Bonferroni-adjusted P-values were also examined as a conservative sensitivity criterion. Each environmental variable was evaluated independently, and statistical significance was assessed at α = 0.05 using both unadjusted and multiple-comparison-adjusted P-values

Results

A total of 534 serum samples from Sonora residents were obtained. The age ranged from 2 to 90 years, with a median age of 33 years; 49% were male (n = 263) and 51% were female (n = 271). Thirty-nine participants (7.3%; 95% CI: 5.3–9.9) tested positive for anti-Coccidioides IgG antibodies, 78 (14.6%) had indeterminate results, and 417 (78.1%) tested negative. Among positive samples, the median IgG value was 2.04 CF EIA units (range, 1.70–2.53), whereas indeterminate samples showed a median of 1.21 CF EIA units (range, 1.07–1.32), and negative samples a median of 0.50 CF EIA units (range, 0.29–0.70).

Among the individuals who tested positive, 56% (n = 22) were male and 44% (n = 17) were female. Their ages ranged from 14 to 90 years, with a median of 42 years. The age distribution showed the highest frequency of positivity among individuals aged 20–29 years (n = 11), followed by moderate counts in the 40–49 and 50–59-year groups (n = 6 each). Lower frequencies were observed among older adults (>70 years). Among the 39 individuals with a positive result, 77% (n = 30) reported no travel history to endemic coccidioidomycosis areas in the USA (Arizona or California). Similarly, among those with negative (314/417, 75%) and indeterminate results (61/78, 78%), the majority reported no travel history to these endemic areas (Table 1).

Table 1.

Key epidemiological findings of Coccidioides spp. IgG seroprevalence in some municipalities of Sonora, Mexico.

Variable	Key Finding	Epidemiological Significance
Overall IgG positivity	7% (95% CI: ∼5%–10%)	Confirms exposure to Coccidioides spp. in Sonora.
Indeterminate results	15%	May reflect low-level or past exposure, suggesting a potential underestimation of true seroprevalence.
Age distribution	Highest seropositivity in young adults and lowest positivity rate was found in older adults	In the case of young people, it suggests greater occupational or environmental exposure, particularly related to outdoor activities, and an efficient immune response. In case of older people, it is related to less environmental exposure, or the exposure may have been temporally distant, and the production of antibodies is almost imperceptible or a weakened immune system by age.
Sex distribution	Slight male predominance	Consistent with previous observations and potentially associated with sexual hormones or behavioral factors.
Travel history	77% reported no travel to the USA	Supports local, autochthonous transmission within the municipalities sampled.

Participants resided in 30 from 72 municipalities of Sonora. Municipality of residence was available for 529 participants; five individuals did not report this information. Thirty-nine seropositive individuals were identified in nine municipalities: Hermosillo (n = 9), Cajeme (n = 6), Guaymas (n = 5), Puerto Peñasco (n = 5), Navojoa (n = 5), Caborca (n = 4), Magdalena de Kino (n = 2), Imuris (n = 1), and Nogales (n = 1) (Fig. 1, Table 2). One additional seropositive participant had unknown municipality of residence.

Figure 1.

Spatial distribution of municipalities in Sonora, Mexico, included in the analysis. Numbers correspond to municipalities as follows: (1) Aconchi, (2) Agua Prieta, (3) Álamos, (4) Benito Juárez, (5) Caborca, (6) Cajeme, (7) Cananea, (8) Empalme, (9) Etchojoa, (10) Fronteras, (11) Guaymas, (12) Hermosillo, (13) Huatabampo, (14) Imuris, (15) Magdalena, (16) Moctezuma, (17) Naco, (18) Nácori Chico, (19) Nacozari de García, (20) Navojoa, (21) Nogales, (22) Opodepe, (23) Puerto Peñasco, (24) San Ignacio Río Muerto, (25) San Luis Río Colorado, (26) San Miguel de Horcasitas, (27) Sáric, (28) Tubutama, (29) Ures, and (30) Villa Pesqueira.

Table 2.

Seroprevalence of anti-Coccidioides antibodies by place of residence in Sonora, Mexico.

Municipality	Specimens tested (n)	Number of specimens
		Positive (%)	Negative (%)
Hermosillo	132	9 (6.8)	123 (93.2)
Nogales	70	1 (1.4)	69 (98.6)
Cajeme	68	6 (8.8)	62 (91.2)
Caborca	51	4 (7.8)	47 (92.2)
Navojoa	49	5 (10.2)	44 (89.8)
Agua Prieta	32	0 (0.0)	32 (100.0)
San Luis Río Colorado	29	0 (0.0)	29 (100.0)
Puerto Peñasco	28	5 (17.9)	23 (82.1)
Guaymas	23	5 (21.7)	18 (78.3)
Magdalena de Kino	14	2 (14.3)	12 (85.7)
Imuris	5	1 (20.0)	4 (80.0)
Unknown	5	1 (20.0)	4(80.0)
Cananea	4	0 (0.0)	4 (100.0)
Etchojoa	3	0 (0.0)	3 (100.0)
Álamos, Empalme, Fronteras, Ures	2 for municipalities	0 (0.0)	8 (100.0)
Aconchi, Benito Juárez, Huatabampo, Moctezuma, Naco, Nacori Chico, Nacozari de García, Opodepe, San Ignacio Río Muerto, San Miguel Horcasitas, Sáric, Tubutama, Villa Pesqueira	1 for municipalities	0 (0.0)	13 (100.0)
TOTAL	534	39 (7.3)	495 (92.7)

The Mann–Whitney U test identified a statistically significant difference only for temperature seasonality (BIO4) between municipalities with and without serological evidence of Coccidioides spp exposure (Table 3, Fig. 2). Municipalities with seropositive individuals showed higher BIO4 values than municipalities without detected seropositive individuals (median: 648.18 vs. 562.11; U = 165.0; unadjusted P = 0.0015). This difference remained statistically significant after correction for multiple comparisons using both Bonferroni and Benjamini–Hochberg FDR procedures (adjusted P = 0.032). No significant differences were observed for the remaining bioclimatic or topographic variables (Fig. 2).

Table 3.

Comparison of environmental variables between municipalities with and without seropositive individuals.

Variable	Municipalities with ≥ 1 positive sample	Municipalities with no positive samples	P-value
Temperature seasonality (BIO4)	Higher	Lower	0.033
Remaining BIO1–BIO19 variables	NS*	NS	>0.05
Elevation	NS	NS	>0.05
Slope	NS	NS	>0.05

^*= not significant.

Figure 2.

Spatial distribution of temperature seasonality (BIO4), municipalities, and urban settlements in Sonora, Mexico. Temperature seasonality (BIO4) represents the standard deviation of monthly mean temperatures and was expressed in°C.

Discussion

In this study, 7.3% of apparently healthy individuals in nine municipalities of Sonora were identified as having anti-Coccidioides IgG antibodies. Based on this finding, the following inferences can be drawn: (1) This result is clear evidence of human population exposure to Coccidioides spp., confirming the active environmental circulation of the fungus in these northern Mexican regions. (2) The proportion of participants with positive IgG results was considerable, given that all individuals were asymptomatic at the time of sampling. This has epidemiological relevance, as it demonstrates that case counts derived solely from clinical diagnosis inevitably underestimate cumulative exposure in endemic communities. (3) Subclinical or mild CM infection is common in the environment of the sampled residents. (4) With no history of travel to known endemic areas in the USA, this result supports the occurrence of autochthonous transmission within these municipalities.

Age-specific analyses confirm epidemiological patterns. The lower positivity rate in older adults (>70 years) may reflect less environmental exposure, but we are more inclined to believe it is due to immunosenescence, since severe cases of CM are reported in this age group in the USA^.2 Regarding sex, the slightly higher seropositivity observed among men is consistent with known epidemiological data on the disease, where the risk of infection is higher in males due to the affinity of Coccidioides spp. for testosterone^.20 These data support the need for public awareness campaigns about Coccidioides and the disease it causes.

The frequency of seropositive individuals in this study varies widely compared to other studies conducted in Sonora^13–15; this difference is due to the techniques used. Previous studies have used the cocci-ST test that measures cellular memory to recent or late contact to Coccidioides spp., whereas the enzyme immunoassay used in this study is optimized to diagnose active disease in symptomatic individuals, when IgG levels are higher, and therefore may fail to detect lower concentrations of antibodies in individuals with resolved or remote infections.¹³, ²¹

Importantly, indeterminate results should not be interpreted as confirmed infection. However, their frequency suggests that the true cumulative exposure to Coccidioides spp. in Sonora may be greater than estimated using strict positivity thresholds alone. From an epidemiological perspective, this ‘gray zone’ may represent a biologically meaningful category rather than mere analytical uncertainty. Similar challenges have been described when serological assays designed for clinical diagnosis are repurposed for population-level exposure studies. Our findings therefore highlight the need to validate assay cutoffs specifically for epidemiological applications in endemic settings and to explore confirmatory strategies such as repeat sampling, immunodiffusion, complement fixation, or longitudinal follow-up.

Temperature seasonality (BIO4) was the only environmental variable that differed significantly between municipalities with and without serological evidence of Coccidioides spp. exposure, and this difference remained significant after correction for multiple comparisons. This finding suggests that annual thermal variability, rather than mean temperature alone, may help distinguish between municipalities where exposure was detected. BIO4 reflects the standard deviation of monthly temperatures and therefore captures the degree of intra-annual thermal fluctuation. In arid and semi-arid environments such as Sonora, strong seasonal temperature contrasts may influence soil moisture dynamics, fungal persistence, and the timing of conditions favorable for growth and airborne dispersal.^21–23

The spatial distribution of positive municipalities also suggests an environmentally structured pattern. Most seropositive individuals were concentrated in municipalities with direct or functional proximity to the Gulf of California, also known as the Sea of Cortés (Puerto Peñasco, Caborca, Hermosillo, Guaymas, and Cajeme), which together accounted for 29 positive individuals. Additional positives were detected in continental municipalities, including Ímuris, Nogales, Magdalena, and Navojoa. Ímuris, Nogales, and Magdalena are geographically clustered in northern Sonora, near the Arizona border and at elevations generally above 500 m, whereas Navojoa, although not directly coastal, belongs to the coastal plain and has relatively low elevations. This pattern suggests that exposure may not be restricted to coastal municipalities but may occur across distinct eco-geographic settings, including the Sonoran Desert lowlands and the piedmont of the Sierra Madre Occidental. In our sample, six of the nine municipalities with positive samples were located in the Sonoran Desert/coastal region, while three were located in the northern piedmont/interior region. The finding that several sampled coastal municipalities, such as Benito Juárez, Huatabampo, San Ignacio Río Muerto, Etchojoa, and Empalme, had no positive samples should also be interpreted with caution because sample sizes in these municipalities were limited. Their negative status should therefore not be interpreted as evidence of absence of environmental suitability or absence of transmission. The ‘‘grow and blow’’ hypothesis provides a useful framework: wetter periods may promote fungal growth, whereas subsequent hot and dry conditions facilitate the aerosolization and dispersal of arthroconidia.²⁴, ²⁵

Historical studies recognized northern Mexico, including Sonora, as part of the endemic region for coccidioidomycosis, based mainly on ecological suitability, clinical cases, and coccidioidin skin-test reactivity.^26–28 These early reports described the relevance of arid and semi-arid environments, high temperatures, low precipitation, desert vegetation, dust-generating soils, and the possible role of wild rodents in maintaining the environmental cycle of Coccidioides spp.^26–28 However, direct recovery of the fungus from environmental samples in Mexico has been rarely documented. Baptista-Rosas et al. noted that only a few positive environmental records had been reported in Mexico, including a historical isolation from soil in Hermosillo, Sonora, and another from Valle de las Palmas, Baja California. This scarcity is consistent with the known difficulty of detecting Coccidioides in soil, where its distribution is highly focal and dependent on local microenvironmental conditions. Therefore, our serological findings should not be interpreted as direct evidence of fungal presence in specific soils, but rather as population-level evidence of exposure that is consistent with historical environmental detection and with the ecological suitability of arid and semi-arid areas of Sonora. Contemporary environmental sampling using molecular methods would be needed to confirm current Coccidioides occurrence in the municipalities where seropositive individuals were identified.

Municipalities with no detected positive individuals should not be interpreted as free of transmission, particularly where sample sizes were very small. Absence of detected seropositivity in sparsely sampled locations more likely reflects limited statistical power than true absence of exposure. This study had several limitations. First, specimens were obtained through convenience sampling from individuals attending clinical laboratories and may not be fully representative of the general population. Second, municipality-level sample sizes were highly unequal, limiting direct geographic comparisons. Third, only IgG responses were analyzed, and no confirmatory assays were performed. Fourth, indeterminate results could not be clinically adjudicated or reassessed with follow-up specimens. Fifth, travel history was recorded only for Arizona and California, two neighboring and well-recognized endemic areas in the USA. Travel to other Mexican states where coccidioidomycosis is also endemic was not explicitly assessed. Therefore, although Sonora represents the state with the highest national burden of hospital discharges associated with coccidioidomycosis, accounting for 51.4% of all hospital discharges recorded in Mexico during 2010–2022 according to official data from the Mexican Ministry of Health dynamic databases, we cannot completely rule out exposure during travel to other endemic regions of Mexico^.4 Finally, the cross-sectional design precludes inference regarding timing of exposure or seroconversion. Despite these limitations, this study offers one of the largest contemporary serological assessments of asymptomatic contact to Coccidioides spp. in Mexico and provides actionable epidemiological insight.

Conclusions

The data support endemic transmission in some municipalities of Sonora, suggest that subclinical disease is common, and indicate that a substantial proportion of the population may exhibit low or borderline antibody reactivity, consistent with prior contact with the pathogen. The environmental analysis identified temperature seasonality as the only variable that differed between municipalities with and without detected seropositive individuals, even after correction for multiple comparisons. This finding suggests that intra-annual thermal variability may be relevant for characterizing areas where exposure occurs. Nevertheless, broader and spatially balanced sampling is needed to confirm this ecological pattern and to evaluate the combined role of climate, soil disturbance, dust generation, wind transport, and human activities in Coccidioides exposure.

The identification of seropositivity among asymptomatic individuals suggests: (1) subclinical infections that may contribute to population immunity; (2) the true burden of coccidioidomycosis remains underestimated; and (3) in vulnerable populations, exposure can be significantly dangerous. Therefore, strengthening diagnostic capacity, implementing targeted serological surveillance, and expanding environmental monitoring will be essential to better define transmission dynamics and establish effective prevention and control strategies in endemic Mexican regions.

Given that coccidioidomycosis is not a notifiable disease in Mexico and surveillance is limited, our results provide a complementary perspective on the hidden burden of the infection.

Author contributions

Edith Sánchez-Paredes (Conceptualization, Data curation, Formal Analysis, Funding acquisition, Investigation, Methodology, Project administration, Resources, Software, Supervision, Validation, Visualization, Writing – original draft, Writing – review & editing), Diego H. Cáceres (Conceptualization, Data curation, Formal Analysis, Funding acquisition, Investigation, Methodology, Project administration, Resources, Software, Supervision, Validation, Visualization, Writing – original draft, Writing – review & editing), Rodrigo Reyes-Macías (Data curation, Investigation, Validation, Writing – review & editing), Sandra Miranda- Mauricio (Data curation, Investigation, Validation, Writing – review & editing), José M Galeana-Pizaña (Data curation, Formal Analysis, Investigation, Methodology, Software, Validation, Visualization, Writing – original draft, Writing – review & editing), Laura R. Castañón-Olivares (Conceptualization, Data curation, Formal Analysis, Funding acquisition, Investigation, Methodology, Project administration, Resources, Software, Supervision, Validation, Visualization, Writing – original draft, Writing – review & editing)

Funding

This work was funded by the Dirección General de Personal Académico, Universidad Nacional Autónoma de México under project No. PAPIIT-IN218722.

Conflict of interest

Since December 2021, Diego H. Caceres has been an IMMY employee, serving as the Latin America Account Manager. All other authors declare no conflict of interest.