An outbreak map covered in colored dots means nothing if you don't know how to read it. Worse, it can mislead you. A cluster of red markers might represent a contained hospital outbreak in a single city or a fast-spreading epidemic across a country. Without understanding what the colors, sizes, and groupings mean, you're just looking at a decorated map.
PandemicAlarm's map is built to give you an accurate global picture in under 30 seconds. Here's how to read it properly.
What do the colors mean?
Each marker on the PandemicAlarm map is color-coded by severity score on a 1-to-5 scale. Green markers (severity 1) indicate routine events that require minimal attention. Yellow markers (severity 2) flag elevated situations worth monitoring. Orange (severity 3) means a serious event with potential to escalate. Red (severity 4) signals sustained transmission or high fatality that warrants active concern. Purple (severity 5) marks events with pandemic potential or confirmed large-scale crisis.
Right now, the DRC Mpox Clade Ib outbreak shows as purple on the map. That's a severity 5 rating, the highest PandemicAlarm assigns. When you see purple, you should be reading every update on that event.
Color alone tells you urgency. But you need more context to understand scale.
What does marker size tell you?
Larger markers represent more severe or higher-impact events. A small green dot is a routine seasonal disease report. A large red circle is a multi-country outbreak with significant case counts and deaths. Size and color work together to create a visual hierarchy so your eye is drawn to the events that matter most.
Compare two markers on the map: a small yellow dot over Germany showing a tick-borne encephalitis seasonal update, and a large red circle over Mozambique showing the active cholera crisis with 12,400+ cases. You immediately know which one demands your attention without reading a single data point.
Marker size scales with a combination of case count, geographic spread, and severity score. A high-severity event with limited cases might show as a medium-sized marker. A moderate-severity event with massive case numbers could appear equally large. Size is a composite signal, not a direct case count visualization.
Why do markers cluster together?
When you view the map at a continental or global zoom level, nearby events merge into clusters. A number on the cluster tells you how many individual events are grouped together. Zoom in and the cluster breaks apart into its individual markers, each representing a distinct outbreak event.
Clustering prevents the map from becoming an unreadable mess of overlapping dots. Sub-Saharan Africa, for example, typically has 15-30 active events at any given time. At full zoom-out, you might see 3-4 clusters. Zooming into West Africa reveals individual events in Nigeria, Sierra Leone, Guinea, and neighboring countries.
Pay attention to cluster density. A region with a single cluster of 3 events looks very different from one with a cluster of 18. High cluster counts in a concentrated area suggest either an active disease corridor or a region with multiple concurrent outbreaks, both of which should raise your alertness if you're planning travel there.
What are pulsing markers?
Markers for severity 4 and 5 events pulse with a slow animation. Pulsing is a visual alarm. When you open the map and see a pulsing marker, that event needs your attention before anything else on the screen.
Only the most serious active events pulse. As of March 2026, you'll see pulsing markers over central Africa (Mpox Clade Ib, severity 5), Mozambique (cholera, severity 4), and the United States (H5N1 dairy spillover, severity 4). Everything else sits still.
Pulsing markers also appear higher in the visual stack, so they render on top of non-pulsing markers if events overlap geographically. You won't miss them.
How do you filter the map?
The filter panel lets you narrow the map view to exactly what you care about. Four primary filters are available.
By status: Show only active events, resolved events, or both. Default view shows active events only.
By severity: Slide to show only events above a threshold. If you're doing a quick travel safety check, filtering for severity 3+ removes the background noise of routine seasonal reports and shows you only the events that might affect your plans.
By disease: Select specific pathogens. Planning a trip to Southeast Asia and worried about dengue? Filter for dengue only and see every active dengue event worldwide. Wondering where cholera is active? One click.
By country or region: Zoom to a specific country and the sidebar populates with all events in that area, or type a country name in the search bar.
Filters combine. You can view "all active cholera events at severity 3 or above" in a single filtered view. Save your filter configuration if you want to check the same view repeatedly.
What do the sidebar event cards show?
Click any marker and a sidebar card opens with structured data about that event. Each card contains the event title, disease name, affected country, severity score, status (active/resolved), confirmed case count, deaths, case fatality rate, date of most recent update, source attribution (WHO DON, CDC, ProMED, etc.), and a brief narrative summary.
Cards also display a "novel" flag when the event involves a newly identified pathogen or strain. Mpox Clade Ib carries this flag because it's a recombinant strain first identified in the current outbreak cycle.
Source links at the bottom of each card take you directly to the original WHO, CDC, or ProMED report. You should follow these links when an event is relevant to you. PandemicAlarm summarizes and scores, but the primary source documents contain clinical detail, transmission data, and public health recommendations that a summary card can't fully capture.
How can you use the map for travel planning?
Start with your destination. Search for the country or zoom in on the region. Note every active marker. Read the event cards for anything at severity 2 or above. Then zoom out slightly and check neighboring countries, because diseases don't respect borders and an outbreak 200 kilometers from your destination in an adjacent country is still relevant.
Cross-reference what you find with the regional disease risk profiles to understand baseline endemic threats that may not have active outbreak markers. A country might show no active malaria alerts on the map because malaria is endemic and expected there, not because malaria isn't present.
Use the severity filter to set a personal threshold. Some travelers accept severity 2 risks with basic precautions. Others won't travel anywhere with an active severity 3+ event. Your threshold depends on your health status, risk tolerance, and the nature of the specific disease involved.
Build a habit of checking the map before any international trip, the same way you check the weather forecast. Weather affects your packing list. Outbreak data can affect whether you should go at all.
For a deeper understanding of the data behind the map, read the pandemic preparedness guide, which covers how severity scores are calculated. For context on how outbreak data flows from clinicians to WHO to your screen, see how WHO tracks outbreaks. Together with this map guide, those three resources give you a complete framework for understanding what you're seeing and what to do about it.