Scorpions in Mexico, and what a house can do

Are there scorpions in Mexico, and where?

Yes, in every state, but the species that make a sting dangerous are concentrated in sixteen of them, along the Pacific side from Sonora to Oaxaca and in the centre of the country. Elsewhere scorpions exist and stings are recorded, in far smaller numbers.

Are there scorpions in Mexico outside those sixteen states? The Health Secretariat's own programme for scorpion stings answers it with a table: every state reports cases, and in 2012 the total was 313,559 stings, 99 per cent of them in 16 states. The same programme places most of them on the Pacific coast states from Sonora to Oaxaca, with Guerrero, Jalisco, Guanajuato, Michoacán and Morelos at the top.

The Secretariat's public page names the sixteen: the Pacific states from Sonora to Oaxaca, and in the centre Durango, Zacatecas, Aguascalientes, Guanajuato, Querétaro, México, Morelos and Puebla. The count has not fallen much since: the national surveillance figures published at the end of 2025 give 302,328 cases in 2025, against 317,941 in 2024.

Which types are found in the areas where owners have houses?

Two of the areas where owners keep houses lie inside the high-risk states, Acapulco in Guerrero and San Miguel de Allende in Guanajuato; two lie outside them, Los Cabos in Baja California Sur and the Caribbean coast in Quintana Roo. The difference shows in the number of stings each state records.

The types of scorpions in Mexico run to some 224 known species, and the Health Secretariat's programme counts only nine of them as being of public-health importance, all of the genus Centruroides. Those nine are the reason the sixteen states are on the list, and the table reads the four states where owners have houses against it.

The list of states comes from the Health Secretariat's page on scorpion stings, and the 2012 figures from the annex of cases by state in the federal programme for their prevention and control. Scorpions in Guanajuato, Mexico, have not become rarer since: the state's own epidemiological bulletin closed 2025 with 58,153 cases, against 60,828 in 2024. What each place asks of a house is on the pages for Acapulco and San Miguel de Allende.

Scorpions in Baja, Mexico, are recorded too, at the scale the table shows: the same annex counts 143 stings in Baja California Sur and 131 in Baja California in 2012, against tens of thousands in Guerrero. Scorpions in Tulum, Mexico, and along the rest of the Caribbean coast follow the Quintana Roo line, 107 stings in 2012. Fewer stings do not mean no scorpions, and a house in Los Cabos or Tulum is checked the same way; it means the check is a matter of routine rather than of risk.

Why do they come into houses, and when?

They come in looking for shelter, and the house is the shelter: most stings happen at night, indoors or in the spaces right next to the house. They come in most in the hot months and the rainy season.

The federal programme describes it plainly: the largest number of stings happen at night inside homes and in the spaces next to them, in yards and sheds, among rubbish and firewood, and the populations most exposed are in the endemic states, with greater incidence in the season of heat and rain.

Where they hide inside is listed in the measures the Health Secretariat published for homes: behind pictures, furniture, calendars and objects hung on the walls. In a house that is lived in, those places are moved and dusted every week. In a house that is closed, nothing moves them for months, and the months in which nobody is there often include the rainy season itself.

What does a house that stands closed for months need?

It needs its entry points closed and its hiding places removed, which is building work, and a check before anyone arrives, which is a visit. The measures are the ones the Health Secretariat lists for any house; what changes is who carries them out while the owner is away.

The Secretariat's page says that scorpion stings can be prevented almost 100 per cent, through measures in the house such as a ceiling lining in the bedrooms, limewash on the outside walls, insect screens and a clean yard. The federal standard that set those measures out in detail, NOM-033-SSA2-2011, was cancelled in 2023, with its content moved into the Secretariat's programmes; its list is still the clearest description of what a house can do.

Chemical treatment has a place, and the Secretariat's programme sets it: pesticides are a complementary measure, applied by health personnel in priority areas. In a private house the order is the same — screens, seals and a clean perimeter first — and this guide names no product and no supplier.

Most of that list is ordinary preventive maintenance: the seals, the skirting, the cut branches and the cleared yard go on the house's calendar with a date, like the roof or the drains.

What does an owner arrange so the house is checked before anyone arrives?

A visit before every arrival that opens the house, shakes out and remakes the beds, checks shoes, towels and stored linen, and looks behind what hangs on the walls. In the high-risk states it is not optional, and anywhere it costs one morning.

The routine is the one the Health Secretariat gives to households: check the bedding before lying down, and clothes and shoes before using them. In a house that has been closed, that check is done the day before the owner or a guest arrives, by the person who opens it, and what was found goes into the report of the visit.

The same visit fixes what it can on the spot and dates the rest: a torn screen, a gap under a door, a branch back against the wall. Over a year, those visits and the work they generate are what an annual plan is for, with the months before the rains as the moment to close the house properly.

Health is one sentence, and it is the Secretariat's: in regions with highly toxic scorpions, any sting is treated at once, by going to the nearest health unit, where the specific treatment is an antivenom given by the doctor. Knowing where that unit is belongs in the house's file, next to the keys.