2016 Leptospirosis surge in New Zealand: A cause for concern

After an entire year of zero infections throughout the entire country in 2015, Northland farmers have reported 7 definite, and one probable, cases of leptospirosis infection in 2016.  This surge in the infection rate has alarm bells ringing at WorkSafe NZ who have been urged by the Medical Office of Health to spread awareness to NZ farmers of the spike in infections.

Also known as 'dairy farm fever' or 'lepto' in NZ, leptospirosis is a serious bacterial infection that affects humans, all forms of livestock, rodents and even domesticated animals such as dogs, especially those that live in close proximity to farms.  New Zealand has an uncharacteristically high infection rate when compared to most European countries.  The bacteria is spread through contaminated urine and water.  Animals most affected are pigs, cows, deer, sheep - as well as hedgehogs, rats, mice and possums.  It has been estimated that 90% of NZ dairy herds have been vaccinated, however only 10% of beef cattle and deer and only 1% of sheep.  This poses a risk to farm workers.

The most likely form of infection for humans comes through direct contact with infected animals or contaminated tissue, urine and water.  Domesticated animals such as dogs that come in contact with infected matter and then spread to humans appears to be a leading cause as well.  Humans can also become infected through indirect contact with infected tissue; only a light spray of contaminated water or urine can be enough to infect a person.

A comprehensive vaccine programme for livestock is the best way to curb the rate of infection, but farm workers are also being warned to check their safety equipment; suits, goggles and gloves, as the infection spreads through cuts, sores and grazes in the skin and even through the mucous membranes of the mouth, eyes and nose.  This means farm workers must be extra careful when cleaning out stockyards and cowsheds.  Protective safety equipment is an absolute must here.  The same goes for people who use urine-contaminated manure as fertiliser for their gardens.  Washing hands after suspected contact with urine-contaminated materials is an absolute must as eating with the hands or smoking can transmit the bacteria and increase infection rate.

Farm workers are not the only people at risk, it must be noted that any people involved in all facets of the agriculture industry can be affected, even through indirect contact.  This includes people working at meat processing plants, livestock transporters and stock yard workers.  The infection is so persistent that reports from European countries have confirmed that people have caught leptospirosis after having spent time in a public park not in the immediate vicinity of any farms.  There have been cases also of forestry workers being infected.

Stock yard workers must be careful when handling livestock, cleaning out pens with high pressure hoses, walking past auction sorting pens and handling contaminated wooden railings and farm equipment.  Just like stock yard workers, transport workers must be careful when handling stock or performing simple routine tasks such as cleaning effluent taps, changing tyres or checking equipment during transit stops, hosing down the truck or during time spent under the truck where contaminated water may have gathered.

An infected human will usually present with a fever, chills and intense headache (basic flu-like symptoms) - though in the worst reported cases, severe abdominal pains, skin rash, internal bleeding, hearing loss, kidney failure and jaundice-like symptoms have also been observed.  Though most people infected with leptospirosis, do not show any signs or symptoms of infection, it is still important to get diagnosed and treated early, as the infection can flare up at a later date.  Treatment is usually through the administration of traditional antibiotics.

In order to reduce an unnecessary spread of leptospirosis infection in your farm or home, it is important to check the vaccine status of your livestock as well as your domesticated animals such as dogs and cats.  Ask your vet about vaccines for dogs.  Wear protective gear whenever in close contact with the animals and their urine.  Monitor animals carefully, especially those presenting with symptoms such as sluggishness, fever or redness of the eyes.

Even after having performed all of the above to avoid leptospirosis infection, as a farm operator it pays to be vigilant as to the overall health and wellbeing of your animals - the traditional vaccine regimen only protects against certain strains of leptospirosis, whilst other strains can still cause infection.

In summary, be on the lookout for symptoms, be careful and take care of your workers by letting them know about the risk of infection and taking preventative measures to protect them.

Most important is to seek medical advice as soon as possible if signs or symptoms arise.  Also, if farm workers become infected with leptospirosis, WorkSafe NZ must be notified immediately.

For more information visit:  http://www.leptospirosis.org.nz/ and http://www.business.govt.nz/worksafe/information-guidance/all-guidance-items/leptospirosis-fact-sheets