Selective pressures exist however in the aquatic environment that may reduce the virulence of V. cholerae. Specifically, animal models indicate that the transcriptional profile of the pathogen changes as it prepares to enter an aquatic environment. This transcriptional change results in a loss of ability of V. cholerae to be cultured on standard media, a phenotype referred to as viable but non-culturable (VBNC) or more conservatively active but non-culturable (ABNC). One study indicates that the culturability of V. cholerae drops 90% within 24 hours of entering the water, and furthermore that this loss in culturability is associated with a loss in virulence.Both toxic and non-toxic strains exist. Non-toxic strains can acquire toxicity through a temperate bacteriophage. Susceptibility
About 100 million bacteria must typically be ingested to cause cholera in a normal healthy adult. This dose, however, is less in those with lowered gastric acidity (for instance those using proton pump inhibitors). Children are also more susceptible, with two- to four-year-olds having the highest rates of infection. Individuals susceptibility to cholera is also affected by their blood type, with those with type O blood being the most susceptible. Persons with lowered immunity, such as persons with AIDS or malnourished children, are more likely to suffer a severe case if they become infected.
Chemical pneumonitis is inflammation of the lung caused by aspirating or inhaling irritants. It is sometimes called a "chemical pneumonia", though it is not infectious. There are two general types of chemical pneumonitis: acute and chronic. Irritants capable of causing chemical pneumonitis include vomitus, barium used in gastro-intestinal imaging, chlorine gas (among other pulmonary agents), ingested gasoline or other petroleum distillates, ingested or skin absorbed pesticides, gases from electroplating, smoke and others. It may also be caused by the use of inhalants. Mendelsons syndrome is a type of chemical pneumonitis. Mineral oil should not be given internally to young children, pets, or anyone with a cough, hiatal hernia, or nocturnal reflux, because it can cause complications such as lipoid pneumonia. Due to its low density, it is easily aspirated into the lungs, where it cannot be removed by the body. In children, if aspirated, the oil can work to prevent normal breathing, resulting in death of brain cells and permanent paralysis and/or brain damage. Signs and symptoms
Acute:

Cough
Difficulty Breathing
Abnormal lung sounds (wet or gurgling sounds when breathing)
Chest pain, tightness or burning sensationChronic:

Persistent cough
Shortness of breath
Increased susceptibility to respiratory illnessSymptoms of chronic chemical pneumonitis may or may not be present, and can take months or years to develop to the point of noticeability. Diagnosis
The pragmatic challenge is to distinguish from aspiration pneumonia with an infectious component because the former does not require antibiotics while the latter does.