Under-ascertainment, under-reporting and timeliness of Iranian communicable disease surveillance system for zoonotic diseases

OBJECTIVES

The important steps in controlling infectious diseases are fast detection, proper treatment and on-time reporting of cases to the appropriate authorities. This study was conducted to evaluate the quality of Iranian communicable diseases surveillance system (CDSS) for zoonotic diseases in rural areas of Fars province (Iran's third largest province).

STUDY DESIGN

The three most important evaluation indices of CDSS, namely under-ascertainment, under-reporting and timeliness, for the three most common zoonotic diseases were measured using independent data source obtained from door-to-door interviews and patients' medical records.

METHODS

Interviews were conducted with 48,771 households in rural areas of Fars province from April 2014 to March 2015. The medical and registration data were obtained from the CDSS and medical or health centres.

RESULTS

Under-ascertainment, total under-reporting and timeliness (delay from the time of onset of symptoms to the time of visiting a medical or health centre, to the time of reporting visited cases to the highest level of CDSS) for leishmaniasis were 19.6%, 42.5% and 81.61 days (48.95 due to system delay), respectively. The corresponding indices for brucellosis were 0%, 41.8% and 56.5 days (22 due to system delay), respectively. For animal bite, the corresponding indices were 7.83%, 13.07% and less than 72 h, respectively (no system delay).

CONCLUSIONS

Although the status of case reporting and timeliness of surveillance system in public sectors providing medical services are clearly better than those of the private sectors, the indices are far from the level needed by CDSS to be able to detect and handle epidemics on time. Training health personnel, especially physicians, from public and private sectors to secure their cooperation along with routine and indebt evaluation are necessary to improve CDSS in Iran.

Molecular detection and conventional identification of leishmania species in reservoir hosts of zoonotic cutaneous leishmaniasis in fars province, South of iran

BACKGROUND

The objectives of our research were to search for Leishmania species in rodents in Fars province, south of Iran, and to compare molecular with conventional methods for detecting these parasites.

METHODS

Rodents were captured using live traps and screened for Leishmania species using molecular and conventional methods, including the taking of smears from each ear. Nested PCR was employed to detect Leishmania in rodents by amplifying a region of the ribosomal RNA amplicon of Leishmania (ITS1-5.8S rRNA-ITS2) that is species-specific by DNA sequence.

RESULTS

Totally, 122 rodents were captured. Leishmania parasites were detected using the nested PCR and three conventional methods (direct smear, NNN culture and Balb/C inoculation. 41 (33.6%) out of 122 rodents had Leishmania infections (34 Meriones lybicus and 7 M. persicus). All PCR products of the ITS-rDNA gene were sequenced. Sequence analysis revealed that 28 out of 41 positive samples were Leishmania major. Thirteen sequences were unreadable and therefore not identified.

CONCLUSION

At least two gerbil species common in Fars ZCL foci, M. lybicus and M. persicus, are acquiring infections of L. major and may be reservoir hosts of one predominant parasite haplotype. Most infections were detected molecularly not by conventional methods, because most rodents died in the traps.