Overseas infectious diseases of priority concern

High-risk exotic diseases, potentially harmful to New Zealand’s health, are those which spread easily, New Zealand people are particularly vulnerable to (eg, non-immune), and can cause severe illness.

Exotic diseases overseas can be spread to New Zealand by New Zealand travellers, visitors, and immigrants. International air travel can spread diseases very quickly across borders. Monitoring high-risk exotic diseases overseas is important because it can inform about the possible exposures of New Zealand travellers, visitors, and immigrants to diseases, and help target our disease prevention and control work.

Public Health Emergencies of International Concern

The World Health Organization (WHO) can declare Public Health Emergencies of International Concern (PHEICs) when public health events arise that have international reach and may require an internationally coordinated response (WHO 2019). At the time of this report, in September 2026, there were two active PHEICs: Polio and Ebola. The PHEIC for Mpox ended on 5 September 2025.

On 17 May 2026, the WHO determined that the Ebola disease caused by the Bundibugyo virus in the Democratic Republic of the Congo and Uganda constitutes a public health emergency of international concern (PHEIC), but does not meet the criteria of pandemic emergency, as defined in the International Health Regulations  (IHR) (WHO 2026). At the time of this report, we do not have sufficient data from the WHO, so we will exclude Ebola from the analysis.

Respiratory illnesses, including measles, non-seasonal influenzas and Middle Eastern Respiratory Syndrome (MERS), are also considered priority notifiable diseases for New Zealand. In addition, Dengue Fever, the most common arboviral disease (disease carried by insects) entering New Zealand, is also reported here.

Polio remained a PHEIC in 2025

Poliomyelitis (polio) is a viral disease that can cause severe neurological disability and sometimes death. In addition to wild cirus, circulating weakened polio virus from oral polio vaccine (cVDPV) may cause polio in places where vaccination coverage is low (Venkatesan 2022). An injectable inactivated polio vaccine has replaced the oral polio vaccine in many countries including New Zealand. From 2022–2025, three countries recorded cases of wild polio virus: Pakistan (131 cases), Afghanistan (54 cases), and Mozambique (8 cases) with all other cases being cVDPV.

Mpox cases were confirmed in 98 countries in 2025

Mpox (renamed from monkeypox by WHO in late 2022) is a viral disease transmitted by contact with skin lesions, body fluids and respiratory droplets. Despite being endemic in Western and Central Africa since 1970, mpox was a low priority disease until 2022 when an increase in global cases resulted in WHO classifying it as a PHEIC in July of that year. While this status was lifted in May 2023, cases remained high in some African countries, particularly the Democratic Republic of the Congo. A surge of cases in mid-2024 led the WHO to declare Mpox as a PHEIC once again in August 2024. As of 2025, Mpox is still declared as a PHEIC with ongoing outbreaks primarily in Africa.

Measles cases increased between 2023 and 2024, and vaccination rates remained low

Measles cases increased between 2023 (82.7 cases per million people) and 2024 (82.8 cases per million people), and vaccination rates remained lower than optimal.

Non-seasonal influenza was reported in 3 countries in 2025

As well as COVID-19, several other highly infectious respiratory diseases have persisted across the globe in recent years. These include non-seasonal influenzas and Middle Eastern Respiratory Syndrome (MERS). Non-seasonal influenzas are defined as any novel influenza strain that may have pandemic potential. These include avian influenzas, such as H5N1, H3N8 and H10N3, and swine influenzas, such as H1N2 and H3N2.

In 2025, human cases of avian and swine influenzas were identified in three countries across two regions, which decreased from 11 countries in 2023 and 10 countries in 2024. All events were contained with sources identified and spread limited to one or two known human cases