European settlers brought new diseases to New Zealand in the early 19th century. Māori had little or no natural immunity to these diseases, so suffered heavy mortality, particularly from measles and influenza.
Early influenza outbreaks among Māori were reported at Foveaux Strait in Southland between 1817 and 1820, and in the Bay of Islands and Mercury Bay in Coromandel in 1838 and 1839. In 1835, measles was reported among Māori working at South Island whaling stations. According to missionary T. A. Pybus: ‘The death rate was serious, and in many cases the people died as they stood. Even in later years skeletons [were] found far from their kaikas (settlements) … lying one across another indicating the suddenness of the end.’1
Early European settlements were often extremely unhealthy, lacking clean water supplies and effective sewage disposal. These conditions assisted the spread of infectious diseases. Typhoid and other bacterial infections were common, along with diphtheria, measles, whooping cough (pertussis), scarlet fever and tuberculosis. Infant mortality rates were high and medical treatments were often ineffective.
Respiratory infections caused many deaths, mostly attributed to bronchitis or pneumonia. Tuberculosis was a constant killer – an endemic epidemic – from this period until the 1950s.
Evidence of epidemics
Evidence for epidemics in New Zealand is imprecise before 1872 because statistics on causes of death were not collected. Even after 1872, misdiagnosis and under-reporting were common. Doctors in the 19th century could not easily distinguish diseases with similar symptoms such as diphtheria, scarlet fever and measles. The cause of an infant death might be entered in official records as diarrhoea or ‘want of breast milk’, when typhoid was the real cause.
Typhoid can usually be treated with antibiotics and rehydration. Untreated case-fatality rates usually vary between 10% and 30%, but can exceed 40%. Untreated typhoid typically follows three distinct stages, each lasting about a week. In the first week, the body temperature rises slowly, and fever fluctuations are seen alongside a headache and cough. High fever, with delirium and agitation, is typical of the second week, along with diarrhoea resembling green-pea soup. In the third week, dehydration and pneumonic complications may accompany the fever. Septicaemia, peritonitis and intestinal perforation are potentially fatal complications.
Typhoid was one of the most common diseases of 19th-century New Zealand. It is transmitted by water, milk or food contaminated by the faeces of an infected person. It is caused by the bacterium Salmonella enterica typhi, which produces symptoms of high fever, sweating, diarrhoea, headache and cough.
Typhoid was most prevalent in fast-growing towns and on the goldfields, where cesspits often leaked into water supplies. Infants and young children were especially vulnerable. Registered typhoid deaths in New Zealand peaked at 323 in 1875.
Typhoid death rates declined in towns and cities as sanitation improved, but remained high in rural and Māori districts well into the 20th century.
In the 19th century, Christchurch was one of the few places with a Board of Health and an active medical officer of health. Dr Courtney Nedwill persuaded the city council to abolish cesspits and switch to a system of pans and ‘night-soil’ collection. This immediately reduced the death-rate from infectious diseases, even before the city completed New Zealand’s first underground sewerage system in 1882.
In 1881, Dr Nedwill investigated a typhoid outbreak in Christchurch and at Sunnyside Asylum, tracing its source to a dairy farm in Lincoln Road. This led to an amendment to the Health Act that enabled the inspection of dairy farms by health officers. Despite this provision, milk-borne typhoid infections continued to cause epidemics in Auckland and other North Island towns until the 1940s.