CDC Surveillance

U.S. Monitoring

How CDC monitors hantavirus disease in the United States — the NNDSS reporting pipeline, the HAN advisory system, and the agency's posture toward the active 2026 MV Hondius cruise cluster, including enhanced case-finding for returning passengers.

Key facts

Active monitored event: MV Hondius cruise cluster
U.S. confirmed (cruise): 0
Notifiable in U.S.: Since 1995
Pipeline: Clinician → State → CDC NNDSS
Clinician alerts: CDC HAN
International picture: WHO Disease Outbreak News

Current monitored event — MV Hondius cluster

CDC is monitoring the WHO-tracked MV Hondius hantavirus cluster through its standard travel-associated surveillance process. The agency has issued clinician-awareness messaging through HAN, asked clinicians to evaluate returning MV Hondius passengers with compatible symptoms, and is coordinating with state and local health departments on suspected reports. No confirmed U.S. Andes-virus cases linked to the cruise have been reported to date; the single U.S. record on the WHO list is inconclusive.

How U.S. surveillance works

Hantavirus infection has been a nationally notifiable condition in the United States since 1995. Suspected cases are reported by clinicians to state or local health departments; confirmed cases flow to CDC through the National Notifiable Diseases Surveillance System (NNDSS) and accumulate on the agency's Reported Cases of Hantavirus Disease page.

Reporting paths

The pipeline from clinician to national surveillance touches several agencies in sequence.

Clinicians notify state or local health departments of suspected hantavirus disease.
State public-health laboratories perform or coordinate confirmatory testing.
Confirmed cases are submitted to CDC via the standardized NNDSS pipeline.
Confirmed totals appear in the weekly NNDSS tables and accumulate in the annual case page.
When clinical or epidemiological context shifts, CDC pushes guidance through the Health Alert Network (HAN).

Where the data lives

Three CDC surfaces hold the canonical U.S. hantavirus record.

Reported Cases of Hantavirus Disease — annual cumulative count and state distribution.
NNDSS weekly tables — newest confirmed records, in near-current order.
HAN advisories — clinician-facing alerts when guidance changes or events emerge.

Lag and revisions

Surveillance data moves on a delay. Newly confirmed cases typically appear in NNDSS one to two weeks after reporting; the annual cumulative page is updated periodically rather than continuously. Records can be reclassified — probable to confirmed, or vice versa — as additional information returns. Read the source date alongside the number.

Where to verify

The CDC Hantavirus pages, the Reported Cases of Hantavirus Disease page, and the NNDSS weekly tables are the authoritative U.S. surfaces. International events are tracked separately through WHO Disease Outbreak News. HantaScan links to all of these from every page footer.

CASE INDEX

Hantavirus surveillance timeline

Date	Location	Status	Cases	Deaths	Source	Signal
2026-05-13	MV Hondius — multi-country South America itinerary International	confirmed	8	3	WHO	WHO Disease Outbreak News third update on the MV Hondius hantavirus cluster: 11 linked records total — 8 laboratory-confirmed, 2 probable, and 1 inconclusive U.S. repatriated traveler. Andes virus identified as the agent of concern. Investigation continues across multiple Member States.
2026-05-08	MV Hondius cluster — WHO update International	surveillance	0	0	WHO	Second WHO Disease Outbreak News update on the MV Hondius cluster raised the confirmed count and described enhanced surveillance for returning passengers across home jurisdictions.
2026-05-05	United States — CDC monitoring posture United States	surveillance	0	0	CDC	CDC announced enhanced case-finding for returning MV Hondius passengers and issued clinician-awareness guidance through HAN. No confirmed U.S. Andes-virus cases linked to the cruise to date; the single U.S. record remains inconclusive.
2026-05-04	MV Hondius cluster — initial WHO report International	surveillance	0	0	WHO	Initial WHO Disease Outbreak News report on a hantavirus cluster linked to the MV Hondius cruise itinerary following Member State notification on May 2. Two confirmed cases and five suspected cases described at first publication.
2025-03-15	United States United States	surveillance	0	0	CDC	CDC and state health departments expanded clinician-awareness messaging on hantavirus pulmonary syndrome following a high-profile case in the rural Southwest that drew renewed national attention.
2023-12-31	United States — cumulative reported total United States	surveillance	864	311	CDC	CDC's Reported Cases of Hantavirus Disease page lists 864 laboratory-confirmed cases of hantavirus pulmonary syndrome in the United States through 2023, with historical case-fatality near 36 percent.
2012-08-16	Yosemite National Park — Curry Village United States	confirmed	10	3	CDC	Ten confirmed HPS cases were tied to the Signature double-walled tent cabins at Curry Village between June and August 2012. Deer-mouse infestation was identified between the cabin walls; the cabins were dismantled and roughly 22,000 visitors were notified.
1995-07-26	United States United States	surveillance	0	0	NNDSS	Hantavirus pulmonary syndrome added to the U.S. list of nationally notifiable diseases, formalizing weekly state-to-CDC case reporting through the National Notifiable Diseases Surveillance System.
1993-11-30	CDC — Atlanta, GA United States	surveillance	0	0	CDC	Sin Nombre virus identified as the etiologic agent of the Four Corners outbreak. The deer mouse (Peromyscus maniculatus) confirmed as the primary U.S. reservoir.
1993-05-14	Four Corners region (AZ · CO · NM · UT) United States	confirmed	17	13	CDC	Cluster of unexplained adult respiratory deaths in the Four Corners region — primarily on the Navajo Nation — prompted the CDC investigation that led to recognition of hantavirus pulmonary syndrome as a new clinical syndrome.

Related on HantaScan

Current Situation MV Hondius Cluster Cruise Itinerary NNDSS Weekly Tables

Primary Sources

CDC Hantavirus CDC Prevention CDC Clinical Overview