71 2024. Pratama et al. Open access under CC BY–SA license, doi:10.20473/mkh.v35i2.2024.71-78 Received: 08-10-2023, Accepted: 01-12-2023, Published online: 10-05-2024 Available at https://e-journal.unair.ac.id/MKH/index Pratama et al. MKH (2024). 71-78 DOI: 10.20473/mkh.v35i2.2024.71-78 Detection of Cryptosporidium spp. in Wild Rats (Rattus spp.) in Surabaya, East Java Ponasari Galuh Pratama 1 , Endang Suprihati 3* , Lucia Tri Suwanti 2,3 , Mufasirin 2,3 , Poedji Hastutiek 3 , Boedi Setiawan 4 , Heni Puspitasari 2 , and Elly Nur Indasari 2 1 Magister Program of Animal Diseases and Veterinary Public Health, Faculty of Veterinary Medicine, 2 Toxoplasma Study Group, Institute of Tropical Disease, 3 Department of Parasitology, Faculty of Veterinary Medicine, Universitas Airlangga, Surabaya 60115, Indonesia 4 Department of Clinic Veteriner, Faculty of Veterinary Medicine, Universitas Airlangga, Surabaya 60115, Indonesia Email: esuprihati@yahoo.co.id ABSTRACT Cryptosporidiosis is a waterborne zoonosis caused by Cryptosporidium, which is a parasite that causes infection of the small intestine and leads to acute diarrhea in both humans and animals. Wild rats (Rattus spp.) are known to carry many zoonotic pathogens including Cryptosporidium. Given their close proximity to humans in urban environments, the likelihood of disease transmission is high. This study aims to detect the Cryptosporidium spp. infection in wild rats in Surabaya City, East Java Province. Intestinal fecal samples were collected using necropsy. The flotation test and Ziehl-Neelsen stain were used to observe the presence of Cryptosporidium under the microscope. The results showed that 69 samples were positive for Cryptosporidium spp. in the oocyst stage, which appeared dark pink with a clear cavity and the size of the oocysts ranged from 2-6 μm. The high incidence of cryptosporidiosis in wild rats is a potential health threat to both animals and humans. Keyword: Cryptosporidium, parasitic disease, Surabaya, wild rats INTRODUCTION Cryptosporidium spp. is an intestinal parasite that causes cryptosporidiosis and was discovered over a century ago. In 1976, the first case of Cryptosporidium infection in humans was reported, namely in an immunocompetent girl and an immunosuppressed adult with symptoms of diarrhea (Gerace et al., 2019). Cryptosporidiosis is a waterborne zoonosis caused by microbial contamination or hazardous substances that are transmitted between living organisms through water (Mufa et al., 2020). According to the World Health Organization (WHO), waterborne diseases are responsible for 4.1% of total deaths worldwide, affecting approximately 1.8 million people annually (WHO, 2006). More than 40 species and genotypes of Cryptosporidium have been identified worldwide (Zahedi et al., 2021). A total of 21 species and 21 genotypes of Cryptosporidium were identified in rodents (Zhao et al., 2019).