# First detection of bovine tuberculosis by Ziehl–Neelsen staining and polymerase chain reaction at dairy farms in the Lekok Sub-District, Pasuruan Regency, and Surabaya region, Indonesia

## TL;DR

This study detected bovine tuberculosis in dairy cattle in Indonesia using PCR and found higher prevalence than traditional staining methods.

## Contribution

The study reports the first detection of bovine TB in specific Indonesian regions using molecular methods alongside conventional techniques.

## Key findings

- 60% of samples in Pasuruan Regency tested positive for Mycobacterium tuberculosis via PCR.
- 70.45% of Surabaya region samples were positive for M. tuberculosis.
- Ziehl–Neelsen staining detected only 13.63% of PCR-positive samples.

## Abstract

Bovine tuberculosis (TB) is a zoonotic disease of great public health importance, particularly in Indonesia, where control measures are limited or are not implemented. This study aimed to detect the presence of Mycobacterium pathogens in milk samples from dairy cattle in Pasuruan regency and Surabaya City, East Java, using Ziehl–Neelsen acid-fast staining and polymerase chain reaction (PCR).

Milk samples were aseptically collected from 50 cattle in the Lekok Subdistrict, Pasuruan Regency, and 44 from dairy farms in the Lakarsantri Subdistrict, Wonocolo Subdistrict, Mulyorejo Subdistrict, and Kenjeran Subdistrict, Surabaya, East Java. To detect Mycobacteria at the species level, each sample was assessed by Ziehl–Neelsen staining and PCR using the RD1 and RD4 genes.

The results of PCR assay from 50 samples in Lekok Subdistrict, Pasuruan Regency showed that 30 samples (60%) were positive for Mycobacterium tuberculosis and two samples (4%) were positive for Mycobacterium bovis, although Ziehl–Neelsen staining did not show the presence of Mycobacterium spp. In the Surabaya region, 31 samples (70.45%) were positive for M. tuberculosis and three samples (6.8%) were positive for M. bovis. Six samples (13.63%) from all PCR-positive samples could be detected microscopically with Ziehl–Neelsen.

The presence of bovine TB in this study supports the importance of using a molecular tool alongside routine surveillance for a better understanding of the epidemiology of bovine TB in East Java.