Disease surveillance and control: Report from the PAHO/WHO Representative in Venezuela

Originally published

Venezuela maintains an alert situation for cholera, dengue, and malaria. Diarrheal and respiratory diseases have increased. Health authorities monitor environmental risks in order to minimize their impact on the health of the affected ones.

The National Epidemiological Surveillance System of the Ministry of Health and Social Development (MOHSD) of Venezuela remains in alert in light of the risks caused by the disaster that occurred two weeks ago and after which there has been an increase in diarrheal and respiratory diseases. Meanwhile, the danger of an increase in cholera, dengue and malaria continues.

The analysis of daily information from established shelters shows some expected results, with an important increase in the report of diarrheal diseases, which became the leading cause of consultation in the second week post-disaster (this corresponds to epidemiological week No. 52). In this regard, an outbreak of diarrhea that affected 80 people occurred in the shelter Poliedro of the Distrito Federal; the outbreak was apparently caused by a common source of food. Respiratory syndrome, including pharyngitis, bronchitis and pneumonia, among other problems, is the second leading cause, followed by viral syndrome, that includes fever and general malaise symptoms. Details on these and other health problems are shown in the following box.

Environmental risks

A series of environmental problems caused by the disaster are a concern of the Venezuelan health authorities. Therefore, in addition to the pertinent control by environmental sanitation experts, epidemiological surveillance specialists are monitoring these risks. Among the principal health hazards identified are non-safe water consumption, the collapse of basic services, overcrowding in shelters and family houses and, in general, the displacement of the affected population.

Environmental risks, such as solid waste accumulation, inadequate food handling, and lack of safe water, were also identified in the shelters. Work for the solution of these risks is carried out locally. For example, in the State of Miranda, wastewater mixed with the water sources (rivers and gorges) that the population utilizes for supply. This has caused consumption of water of poor quality, which increases the risks of acquiring water-borne diseases, especially diarrheal diseases and cholera.

Health monitoring by groups of diseases

To achieve better surveillance and disease control after the disaster, the Venezuelan health authorities activated what is called the "daily syndromic report", that implies a follow-up of the epidemiological behavior by groups of diseases, that is, by syndromes. The main ones that are being considered are the respiratory, the diarrheal, the dermatological and the febrile. The purpose of syndromic surveillance is to anticipate the detection of outbreaks of specific diseases for their immediate control.

The Epidemiological Surveillance System of Venezuela, which continued with the immediate report of diseases and special events as cholera, meningoccocal meningitis, measles, diphtheria, whooping cough, and yellow fever, among others, has also intensified the compulsory notification of the communicable diseases in the affected population. Cholera, Malaria, Dengue, Leptospirosis, Rabies, Venezuelan Equine Encephalitis, among others, are the main diseases considered as tracer indicators.

Authorities have planned to carry out assessments in the shelters to determine the extent of problems of mental health, depressions, alcohol abuse, physical and sexual violence, which can affect the health of these populations.


Since October 1999, malaria began to increase in Venezuela, as shown by data corresponding to the epidemiological week No. 40, that includes from days 3 to 9 of that month. The disaster of December found the disease in a process of increase, implying a greater risk for the populations of the affected states where malaria is present.

Accordingly, cases reported during the week after the disaster (epidemiological week No. 51) were 628, figure that represents 100 cases more with respect to the previous week. The states in epidemic situation are Amazonas, Anzoategui, Portuguesaa, and Zulia. Among the states affected by the disaster, Sucre is in alarm of high risk for Malaria.

Cases of malaria increased starting in the week 40 (in October) and the majority of the states affected by the floods are at malarious risk. The state Sucre (red above) currently is that of higher risk in the area of emergency.


In the case of dengue, Venezuela entered in a state of epidemic in the third week of December. The most affected states are Anzoategui, Carabobo, Falcon, Merida, and Zulia. All of them, except for Merida, were affected by the floods. From 19 to 25 December (epidemiological week N°51) a total of 26,277 cases accumulated, of which 2,615 correspond to dengue hemorrhagic fever. Fifteen of them 15 died, which represents a case-fatality rate of 0.5%.

The cumulative incidence in 1999 shows an epidemic situation in the states Barinas, Falcon, Nueva Esparta, Portuguesa, Sucre, and Zulia. Four of them were affected by the disaster.

Dengue is currently affecting all the Venezuelan states. Those which report greater number of cases are Zulia, Falcón, and Federal District.


Cholera, reintroduced in Venezuela in 1996, increased during 1999 and, upon the floods of December, the authorities are in alert for the risk that the disease represents. The greatest problem is located in Sucre and in Miranda, states affected by the disaster and that are in a cholera epidemic situation.

A total of 13 new cases were reported in Sucre in the last week of December (week epidemiological No. 52), totalling 237 cases during the year. The State of Anzoategui reported a laboratory-confirmed case. Measures to control of the focus were carried out, remaining pending the serological classification. The cumulative total in the five states of the country where the disease is present reached 376 cases, figure that represents 63 cases more than in the same period of 1998.

Because Cholera is a disease subject to immediate report, up-to-date data are available as of 31 December.

TOTAL 1998
Delta Amacuro
237 (*)
Nueva Esparta
Source: Ministry of Health and Social Development

(*) Accumulated number was corrected Actions carried out

The PAHO Representative Office in Venezuela, in coordination with the Office of the Director of Epidemiology, is supporting and participating in the development of the Health Situation Room for the Disaster in the Ministry of Health and Social Development. In the same way, PAHO is already collaborating in Zulia and Falcon and shortly in the states Vargas and Miranda.

Advisory and supervision visits have been carried out to the state of Sucre, after the case reporting of cholera, and to support the plan of action and requirements of the health team in the state of Miranda; both states were affected by the floods.

In the states Vargas and Miranda, the most affected by the tragedy, plans of local action for surveillance and disease and environmental risks are being supported.

The Ministry of Health and Social Development, with the support of PAHO-WHO, has programmed a national meeting with several of its Directorates and the regional health directors for 5 and 6 January. The objective is to coordinate actions in light of the national emergency.

Urgent needs of the country

  • Strengthen epidemiological surveillance in the affected states and at local level.
  • Stregthen epidemiological surveillance in the shelters.
  • Creation of health situation rooms in the affected states.