About biosecurity and border health
This section provides background information about biosecurity and vector-borne diseases in New Zealand, and infectious diseases around the world.
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Why is biosecurity important for health?
Why is border health important for health?
Biosecurity surveillance and intervention
The risk of vector-borne diseases in New Zealand
Dengue fever and malaria
Global spread of infectious diseases
Biosecurity is important for health, as it reduces the risk and spread of pests and diseases, including vector-borne diseases. More broadly, biosecurity helps protect the economy, environment and health of New Zealand’s population from unwanted exotic pests and diseases. Biosecurity is led by Ministry for Primary Industries in New Zealand.
Vector-borne diseases occur when a virus, protozoan (single-cell organism) or bacterium, carried by mosquitos, sand flies or ticks, is transmitted to humans. Mosquitos, sand flies and ticks are examples of ‘vectors’. Malaria and dengue fever are examples of vector-borne diseases.
As well as vector-borne diseases, infectious diseases may also spread internationally.
Border health protection aims to limit and respond to the international spread of infectious diseases, and other public health threats. Border health measures aim to protect the health and wellbeing of international travellers, aircraft and ship crew, and the general public.
Border health is led by the Ministry of Health. Regional health authorities also work with other agencies with border control responsibilities.
Biosecurity surveillance and intervention in New Zealand occurs at three stages (figure 1):
The risk of vectors and infectious diseases entering New Zealand reduces at each stage. Biosecurity is more cost-effective than reacting to the health and/or economic impact from an outbreak.
Figure 1: New Zealand’s biosecurity system
The risk of vector-borne disease in New Zealand is low. However, it is important to monitor vector-borne disease, due to several factors that could increase our risk:
- increasing movement of people and goods worldwide
- climate change potentially creating more suitable habitats for vectors in New Zealand
- the close proximity of, and close relations with, a number of countries in the Western Pacific and South East Asia, where vector-borne diseases are endemic.
For these reasons, it is important that New Zealand maintains its vigilance and biosecurity surveillance.
Dengue fever and malaria are examples of vector-borne diseases.
Dengue fever is a viral disease transmitted by mosquitoes. It is prevalent throughout the tropics and subtropics.
Dengue fever is the world's fastest growing vector-borne disease, including in the Asia Pacific region . Its incidence has increased 30-fold over the last 50 years . Around 40 percent of the world’s population is now at risk from dengue fever. Each year, about 390 million dengue fever infections occur in over 100 countries.
Each World Health Day, the World Health Organization (WHO) selects a theme that highlights a global public health issue. The theme for 2014 is vector-borne diseases, with a first-time focus on dengue fever .
Malaria is a disease caused by the parasite Plasmodium, and is transmitted by mosquitoes. It kills over 1.2 million people annually , and is a leading cause of death and disease in many developing countries. Young children and pregnant women are the groups most affected.
Some types of malaria can stay at a dormant stage and hide in the liver for weeks and even years. A relapse may occur at a later date.
Infectious disease outbreaks around the world are also a risk to public health in New Zealand. These diseases could enter New Zealand through travellers, animals or on objects carrying infectious organisms (fomites).
The Ministry of Health and public health units of District Health Boards are responsible for public health protection of New Zealand, including relating to the border. These organisations work together to limit and respond to the spread of diseases and other public health threats.
The Global Alert and Response system run by the World Health Organization provides information about international disease outbreaks.
1. MAF Biosecurity New Zealand. 2009. Biosecurity Surveillance Strategy 2020. Wellington: MAF Biosecurity New Zealand. Available online: http://www.biosecurity.govt.nz/surveillancestrategy
2. Arima Y, Matsui T. 2011. Epidemiologic update on the dengue situation in the Western Pacific Region. Western Pacific Surveillance and Response Journal 2(2): 4-8. doi: 10.5365/wpsar.2011.2.2.005
3. World Health Organization. 2014. World Health Day – Vector-Borne Diseases. Retrieved 27/05/2014, from http://www.cdc.gov/Features/worldhealthday2014/
4. World Health Organization. 2014. Vector-borne disease. Retrieved 27/05/2014, from http://www.who.int/heli/risks/vectors/vector/en/