Readers in Mexico have been emailing the BBC describing the sense of fear gripping the country as a result of a flu virus outbreak, which has so far claimed up to 60 lives.
The World Health Organization says the virus has the potential to become a pandemic.
Read a selection of BBC readers' comments below.
I work as a resident doctor in one of the biggest hospitals in Mexico City and sadly, the situation is far from "under control". As a doctor, I realise that the media does not report the truth. Authorities distributed vaccines among all the medical personnel with no results, because two of my partners who worked in this hospital (interns) were killed by this new virus in less than six days even though they were vaccinated as all of us were. The official number of deaths is 20, nevertheless, the true number of victims are more than 200. I understand that we must avoid to panic, but telling the truth it might be better now to prevent and avoid more deaths.
Yeny Gregorio Dávila, Mexico City
The situation in Mexico City is really not normal. There is a sense of uncertainty that borders on paranoid behaviour in some cases. At this very moment, Mexican TV is showing how military forces are giving masks to the people in the streets. Moreover the news is sending alarming messages for the audience. Really, the atmosphere in the city is unsettling, a good example: pubs and concerts are being closed or cancelled and people don't haven thorough information. In this city (and country) there is an urgent need for assertive information, no paranoid messages from the government or the Mexican media.
Patricio Barrientos and Aranzazu Nuñez, Mexico City
Massive events have been cancelled at the National Auditorium - Mexico City's largest indoor venue with capacity of 10,000 - which has been closed. Two soccer games have been cancelled at the Olympic Stadium. A sold out game with 70,000 expected attendance will be played behind closed doors. Another game at the famous Azteca Stadium that would draw an attendance of 50,000 will also be played behind closed doors.
Juan Carlos Leon Calderon, Mexico City
It's eerily quiet here in the capital. Lots of people with masks, Facebook communities exchanging gallows humour, everybody waiting to see if schools and universities will stay closed for ten days (as goes the rumour). All masks have been used up, and we are waiting for new supplies.
Dr Duncan Wood, Mexico City
We will be sick soon and, well, do the math - 400 can infect at least another two per day
Adriana, Mexico City
Yesterday in my office it was a bit surreal walking in to see all in blue masks with deep cleansing of computer equipment and surfaces going on. Let's hope it is contained and does not escalate. The local news is reporting 200 fatalities and reports of flu spreading from areas outside of Mexico City. Given the volume of daily commuter traffic on cramped busses and trains, this may not have to be too virulent to be disastrous in human terms. I wonder what controls there will be on flights in and out.
Will Shea, Mexico City
I work for the government as a head of a computer infrastructure operations department. At work we are doing several actions to try not to expose workers. We sent several home. I support the Pumas football team and the very important match with the Guadalajara team will be played behind closed doors. My family and I are going to stay home all weekend. We feel a little scared and confused with the feeling that we are not given being told the truth. Many people think the numbers of dead people is higher than we are being told.
Marcos, Mexico City
The whole city is affected, I have a very bad feeling about this. Two of my friends at work are sick, they were sick for a couple of days, they went to the hospital and they sent them back to work. The doctor told them it was just a flu until Friday when the alarm was spread, then they were allowed to go home. I work in a call centre and I'm worried because there are no windows in the building so it cannot be ventilated and around 400 people work there.
We all have talked to our supervisor but no one has done anything not even sterilise or disinfect the area. We will be sick soon and, well, do the math - 400 can infect at least another two per day. The authorities say there's nothing they can do since it's a private company and I can assure you, the company I work for is not the only one like this in the whole city. Us workers don't have much protection from our government and if we want to keep our jobs we have to go anyway.
Adriana, Mexico City
My sister got influenza like symptoms two weeks ago. She is fine now, thank god, but similar cases have been showing up since two weeks ago. I work for a bank and we were told to take our laptops because there is a high possibility to work from home. I have gone out to buy some face masks.
Ruben Farfan, Mexico City
I'm a college student in Mexico City, and I can only say that the information that the media has provided doesn't seem to be enough, we do not now how serious it is because they have failed to mention it. There have been two ways of responding to this event, the ones that have entered themselves into quarantine claiming that the government is hiding something much more serious, and those who take this as a joke saying that everyone is overreacting. To put a cherry on top all kind of crazy rumours are flying around - that they are going to quarantine Mexico City, that a school and some specific branches of offices and jobs are going to be suspended for days to come, and so on. I wish more info was available, for example how to prevent it? Have there been many deaths? Is there a threat of an epidemic?
Mari A, Mexico City
I didn't hear about the flu epidemic until last night at 2330. Yesterday the streets were almost empty compared to a normal Friday afternoon. The media is bombarding the same information over and over again, but the authorities haven't said anything new yet, only that they have enough vaccines for those with the flu and that we should avoid public spaces.
Paulina, Mexico City
This is another blow to the tourism industry in Mexico, even though non of the events that is taken place is anywhere near the tourist areas of Cancun, Playa del Carmen or Puerto Vallarta, the news comes across as all of Mexico is affected! After wrong reports of drug related violence, military presence etc. in Cancun, which hurt the industry tremendously, now people think that all of Mexico is affected by a virus that is mostly present in the capital. I guess the problem is that this is a country where the capital carries the same name as the country, thus when people hear news about Mexico, albeit it refers to Mexico City, they assume it is affecting the whole country.