Some gases pose a real danger to members of the public, and also to forensic pathologists, a number of whom have been injured by gases.

Once a colleague of mine was tasked to perform a repeat autopsy on a body from a private undertaking company. Three mortuary technicians winched the lid off the wooden coffin, which had been tightly sealed with metal screws. As they opened the coffin, all three were overcome by toxic gas, and soon thereafter were rushed to hospital. They developed pulmonary oedema from chemical injury to their lungs. Two were discharged within the week, the third spent three weeks in hospital.

What was the chemical gas which had so injured my colleagues?

The private undertaker had learned that a cup of granulated chlorine placed in a mortuary fridge would dispel unpleasant odours. (It is magical stuff and works better than most sprays or fragrances.) The undertaker adopted this method and developed the secret practice of sprinkling granulated chlorine into coffins around deceased individuals. In retrospect, one can hardly blame the person for his ingenuity; his motto, after all, was to deliver “a clean and serious service”.

What the undertaker did not take into consideration was that when a body decomposes, purge fluids are released, which tend to react with the chlorine granules, creating chlorine gas. Chlorine gas is pale green, irritant and toxic: it’s dangerous and even deadly.

One of the most toxic gases is formaldehyde, which is used to preserve tissues. Long-term inhalation of formaldehyde has been associated with an increased risk for all cancers of the lung and nasal passages.

Forensic pathologists and mortuary technicians are sometimes also exposed to cyanide when performing autopsies on persons who have ingested this substance. Although cyanide can volatilise from autopsy tissues, the major risk to autopsy personnel occurs when the stomach is opened. In the acidic environment, cyanide salts are converted to highly volatile hydrocyanide gas.

Exposure to gastric contents and clothing contaminated with organophosphate poisoning can be dangerous too. Poisoning can be very surreptitious. There have even been cases of people being poisoned from chair covers which had been contaminated by poison during transport.

*****

In another case, a 59-year-old male died suddenly at his home seven days after he had become aware of a bite of unknown origin on the back of his neck. He neither removed nor witnessed an insect on his neck. There was a report of a non-specific headache prior to his death. No other complaints were noted. It was suspected to be a spider bite, yet he did not seek medical help and no further medical records were available. The incident took place during the Covid-19 pandemic and it is unclear whether that may have deterred him from seeking medical assistance.

His body was referred for medico-legal investigation in accordance with South Africa’s Inquests Act, Act 58 of 1959. The body was thin and showed poor or average nutrition (height 1.85m; weight 80kg). An eschar measuring 1.5cm x 1.2cm was found on the back of his neck. An eschar is a dry, dark scab or falling away of dead skin, typically caused by a burn, an insect bite or an infection with anthrax. The wound showed signs of healing.

Approximately 4cm to the right of the eschar was an ulcer 0.5cm in diameter (possibly another, smaller eschar — sometimes multiple bites are noted). Both wounds were excised for histological purposes. No further injuries or abnormalities to the body could be identified. There were multiple co-morbid factors present, such as background lung, heart and kidney disease. Examination of the blood vessels showed no obvious microthrombi (blood clots).

I immediately realised that this was not a case of a spider bite. It was more in keeping with a tick bite, because of the eschar. This prompted swift, specific investigations of other possible infectious causes of death. Post-mortem venous blood was sent to the laboratory for analysis and the results came back positive for Rickettsia conorii, which at the time of death supported my provisional diagnosis of tick bite fever.

In South Africa, tick bite fever is associated with either R. conorii or R. africae, infection with the former known to be associated with higher mortality and poorer clinical outcomes. The classical clinical triad for tick bite fever diagnosis is eschar, fever and rash, however, all three features are only found in approximately 50% to 75% of cases. My patient had no evidence of any rash, and no fever was reported.

R. conorii is mostly associated with dog and kennel ticks and is often reported in peri-urban or domestic locations in South Africa, and therefore exposure is plausible. Larvae or nymph stages of ticks may be missed due to their small size. It is not clear if the deceased felt the bite or discovered the eschar; it is unlikely that he would have been bitten only seven days prior to death, as the incubation period following a bite is typically five to seven days, and one would expect some clinical progression before death. Microscopic examination confirmed eschar formation. The absolute reason why he died remains elusive. The multiple co-morbid factors, plus the tick bite, together could possibly have contributed to his death.

Tick bite fever is a common cause of fever-based illness in South Africa and timely treatment with antibiotics such as doxycycline or chloramphenicol can be lifesaving.

Interestingly, several days after having performed the autopsy examination, I started feeling sick and developed joint pains and a headache. After all, I had entered the postmortem thinking it was a spider bite and I was therefore somewhat relaxed with my personal protective equipment. I didn’t predict that I would be dealing with a possible transmissible infectious disease. My own GP placed me on doxycycline and I lived to tell this tale. DM

Ryan Blumenthal is a South African forensic pathologist with more than 20 years’ experience in the field. His book “Autopsy: Life in the Trenches with a Forensic Pathologist in Africa”, which was published by Jonathan Ball in August 2020, is a non-fiction bestseller in South Africa. His eight-part documentary, “Lightning Pathologist” was aired from 9 to 20 November 2020 on People°s Weather (Channel 180) on DStv. It was viewed by over 2.2 million people.