Cuba's Battle Against the Viruses Threatening Its Crops
In Cuba's fields, a silent war has been waged for decades. A conflict where the soldiers wear white coats and carry microscopes, and the enemy is a thousand times smaller than a grain of sand: plant viruses. These invisible pathogens have threatened strategic crops like sugarcane, tobacco, and tomatoes, putting the island's food security at risk. Cuban plant virology, forged under exceptional conditions, represents a story of scientific ingenuity in the face of geopolitical and economic adversity. 1
Plant viruses cause an estimated $60 billion in crop losses worldwide annually.
Cuban virology rests on the shoulders of giants like Carlos J. Finlay, who introduced the first microscope to Cuba in 1885. Although known for his work with yellow fever, Finlay laid the technical foundations by establishing the Histobacteriological Laboratory and Anti-Rabies Institute of Havana (1887), the first of its kind in Latin America. Along with him, bacteriologist Juan N. Dávalos promoted native microbiological research, creating a scientific culture that would later allow the study of plant pathogens. 1
After 1959, agricultural health was prioritized. In 1976, the new political-administrative division led to the creation of the Provincial Plant Health Council (CPSV) in Santiago de Cuba. By 1977, the Provincial Plant Health Laboratory (Laprosav) was already functioning, equipped with specialized areas in entomology, mycology, and critically, virology. Figures like engineers Darwin de Azúa (director of Laprosav) and Zenaida Díaz Meriño (entomology) led these efforts. 2
| Sample | Absorbance (405 nm) | Diagnosis |
|---|---|---|
| Healthy control | 0.12 | Negative |
| Field 1 | 1.85 | Positive |
| Field 2 | 0.90 | Positive |
This experiment (conducted at Laprosav in the 1980s) allowed identification of epidemic foci in Pinar del Río, reducing losses by 70%. The ELISA technique, described by Clark and Adams in 1977, was adapted using local reagents and in-house produced conjugates, overcoming import limitations.
| Reagent/Tool | Function | Cuban Example |
|---|---|---|
| Specific antibodies | Immunological detection of viruses | Production in rabbits (Tomato mosaic virus) |
| Electron microscopy | Direct visualization of viral particles | Identification of Geminivirus (1990s) |
| Real-time PCR | Viral DNA/RNA amplification | Diagnosis of phytoplasmas in citrus |
| Indicator plants | Bioassay through symptoms | Chenopodium quinoa for tobamovirus |
| Rapid diagnostic kits | Field detection in <30 min | Immunochromatographic strips for banana |
Key achievement: Adaptation of ELISA techniques with limited resources.
Impact: Mass detection of viruses in imported tomato seeds, preventing introduction of Tomato yellow leaf curl virus.
Innovation: Introduction of RT-PCR for RNA viruses (e.g., Sugarcane yellow leaf virus).
Challenge: Access to thermocyclers and enzymes during the Special Period. Solution: Use of equipment donated by FAO and collaboration with INTA-Argentina.
Advanced techniques: Next-generation sequencing (NGS) to identify emerging viruses.
Success case: Identification of a new Cilevirus in citrus using MinION (portable sequencer).
Cuban plant virology is a model of resilience. From Finlay's microscopes to cutting-edge sequencers, island scientists have transformed limitations into innovation. Today, a network of 8 Territorial Plant Protection Stations monitors crops, while the National Center for Plant Health develops accessible diagnostic kits. This story, written between test tubes and crop fields, demonstrates that the battle against invisible viruses is won with knowledge, collaboration, and an unwavering commitment to the land. 2
"Some fight against visible oppressions; we fight against the invisible ones. But both wars liberate" — Adapted from Carlos J. Finlay (1881). 1