By Geradine Ohonba

Health Editor/Columnist

Executive summary (Jan–Aug 2025)

January 2025

• WHO flagged elevated acute respiratory infections in northern China (seasonal mix of influenza/RSV/rhinovirus), without novel pathogen signals.

• Lassa fever season began in Nigeria with 54 confirmed cases in epi-week 1 across multiple states.

February 2025

• U.S. reported its last human H5N1 cases of the winter; CDC later noted no additional cases through mid-year.

• Nigeria’s diphtheria surveillance still detected suspected cases, but confirmed counts trended lower than late-2024 peaks.

March–April 2025

• Measles flare-ups emerged across the Americas; Belize confirmed its first cases since 1991 (travel-associated, unvaccinated teens).

• U.S. regulators continued investigations of H5N1 in dairy products and cattle; USDA/APHIS and FDA issued testing updates.

May 2025

• Measles in the Americas surpassed 2,300 confirmed cases through EW16; PAHO urged gap-closing campaigns.

• Mainland China notified WHO of a human H5N1 case (likely exposure in Vietnam) that recovered—first such report since 2024.

June 2025

• WHO’s mpox situation report highlighted sustained transmission in multiple African countries (e.g., Sierra Leone), even as some locations saw declines.

• Nigeria’s Lassa fever cumulative burden reached >700 confirmed by mid-June with CFR ~19%.

July 2025

• Chikungunya: WHO and media noted rising international concern and travel advisories under consideration; several European nations reported local detections of chikungunya/dengue.

• U.S. CDC ended its H5N1 emergency activation and folded updates into routine influenza reporting (no human cases since February).

• Cholera risks escalated across West and Central Africa at the start of rainy season; UNICEF estimated 80,000 children at high risk.

August 2025

• WHO DG (Aug 7) updated that >30,000 mpox cases and 119 deaths were reported globally in H1-2025; 23 African countries continue outbreaks.

• Legionnaires’ disease cluster in Central Harlem: NYC Health provided updates on cases, exposures, and building sources under investigation; local journalism later reported four deaths.

• Cholera in Sudan/Darfur intensified (worst in years), with treatment centers overwhelmed; Angola reported 27,722 cases and 776 deaths to Aug 2. Haiti reported >2,500 suspected cases since January amid displacement.

• Oropouche virus update: PAHO tallied 12,786 confirmed cases in the region through late July, heavily concentrated in Brazil, with imported cases in several countries.

• Measles: PAHO announced 10 countries with outbreaks; U.S. CDC reported 1,356 cases across 41 jurisdictions as of Aug 5.

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2) Thematic deep-dives

A. Vector-borne diseases

Dengue

• ECDC’s global synthesis (Aug 5) estimated ~3.6 million cases and >1,900 deaths reported in 2025 across 94 countries/territories—continuing the multi-regional surge that began in 2025