Are AI chatbots ready for chikungunya public education? Evidence on validity, reliability, and readability

BACKGROUND: Chikungunya continues to expand geographically, driving demand for trustworthy, easy-to-read public guidance. Conversational AI systems are increasingly used for health information, yet their medical validity, reliability, and readability remain uneven. METHODS: We evaluated four widely used chatbots (ChatGPT, Claude, DeepSeek, Gemini) on two task sets: (1) validity on a 50-item single-answer MCQ dataset about Chikungunya; and (2) reliability and readability on 13 core public-education questions derived from Google Trends "topics" and clinician. Reliability was scored with DISCERN, EQIP, GQS, and JAMA benchmarks by clinician raters; readability used ARI, CL, FKGL, FRES, GFI, and SMOG. RESULTS: Across three independent runs, Deepseek-V3.2 achieved the highest MCQ accuracy (86.7%); other models ranged near 72-78% accuracy. In paired brand-line comparisons, newer iterations outperformed predecessors: ChatGPT-5 vs. ChatGPT-4o showed a 5.3-percentage-point gain, and Deepseek-V3.2 vs. Deepseek-R1 showed an 8.7-point gain in accuracy. Reliability (DISCERN, EQIP, GQS, and JAMA) differed significantly across models (p < 0.05). Pairwise tests favored Deepseek-V3.2 on most instruments, though absolute JAMA scores were low for all systems, indicating limited transparency signals. Readability (ARI, CL, FKGL, FRES, GFI, and SMOG) also differed significantly (p < 0.05). Deepseek-V3.2 produced the easiest text on average, Gemini the most complex, and no model met the sixth-grade benchmark. CONCLUSION: Under the benchmark conditions of this study, newer chatbot iterations showed higher factual performance, and DeepSeek-V3.2 achieved the strongest task-specific answer-quality metrics. However, these findings should not be interpreted as evidence of readiness for public-health deployment or as an endorsement of any platform. Transparency remained limited, readability exceeded recommended public-facing levels, and platform-level concerns (including privacy, data governance, content moderation, and sociopolitical acceptability) remain essential considerations. Chatbots should therefore be treated as supervised adjuncts to, not substitutes for, authoritative public-health communication.