Hasil-hasil investigasi epidemiologi akan sangat membantu para dokter hewan untukmemperoleh informasi dalam penanganan suatu penyakit. Demikian pula investigasi epidemiologi pada manajemen orangutan di Kebun Binatang Ragunan, akan sangat bermanfaat memberikan informasi dan data di dalam menyelenggarakan pengelolaan orangutan di Kebun Binatang Ragunan. Data tingkah laku orangutan di dalam kandang, sistem perkandangan, mutu dan jumlah pakan yang diberikan, catatan tentang status kesehatan, uji tuberkulinasi, hematologi normal, elektrokardiogram normal, kimia klinik normal, prosedur kontrasepsi, kesemuanya ini bisa dipakai di dalam pengelolaan kesehatan orangutan di Kebun Binatang Ragunan. Populasi orangutan kalimantan di alam makin lama makin menurun, antara lain disebabkan oleh perburuan liar. Oleh karena itu bagaimanapun juga usaha reintroduksi harus dilakukan secara berkesinambungan pula. Untuk tujuan itu diperlukan generasi orangutan yang memenuhi sarat untuk di reintroduksikan ke alam. Jadi Kebun Binatang harus mampu menghasilkan generasi orangutan yang sehat, tidak berpenyakit menular, tidak mengidap endoparasit, ektoparasit, serta tetap memiliki sifat-sifat alaminya. Orangutan termasuk anggota kera besar yang mempunyai kantung udara luas dan berkelok-kelok, sehingga memudahkan terjadinya infeksi yang bersifat kronis. Pada umumnya radang kantong udara pada orangutan kalimantan di Kebun Binatang Surabaya dart Kebun Binatang di Luar Negeri kesemuanya bersifat kronis. Dan eksudatnya dapat diisolasi bakteria Pseudomonas aerugenosa, Proteus vulganis, Escherechia coll. Bakteri-bakteri ini pada umurnnya bukan patogen juga terhadap manusia, tetapi pada isolasi kuman dari eksudat radang kantong udara pada orangutan jantan di Kebun Binatang Ragunan juga ditemukan bakteri Streptococcus pneumoniae yang sangat patogen terhadap manusia, satwa liar, hewan ternak dan hewan kesayangan. Bahkan Streptococcus pneumoniae ini bisa menular dari satwa kepada manusia yang disebut zoonosis dan dari manusia ke satwa yang disebut anthropozoonosis. Radang kantong udara pada orangutan Kalimantan di Kebun Binatang Ragunan dan Kebun Binatang Surabaya ini, baru pertama kali dilaporkan di Indonesia. Ditemukannya bakteri Streptococcus pneumoniae di eksudat radang kantong udara pada orangutan di Kebun Binatang Ragunan juga baru pertama kali dilaporkan.

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Kalimantan orangutan ( Pongo pygmaeus pygmaeus, Hoppius, 1763) is member of the great ape group which is endemic in Kalimantan island of Indonesia. Its fur color is reddish, dark or light brown. The fur is quite long and dense, especially at the shoulders and arms. Its head rump length (HRL) is approximately 1.25 - 1.5 meters (exceptionally, the HRL might reach 1.8 meters). The average body weight of the female is about 40 kg and of the male is about 75 - 100 kg. The orangutans is highly adapted to an arboreal mode of life, therefore it is considered as the true arboreal member of the great ape group. It explores the jungle of Kalimantan by swinging from branch to another branch of the tree. Its swinging movement is supported by its arms, which are longer and stronger than the arms of the other great apes. Its arms spread is about 2.25 meters. Most of the males have large cheek flanges which consist of fibrous tissue, at the side of the face. The width and length of the cheek flanges mature male is about 10 centimeters and 20 centimeters respectively. It also has a throat sac, which is called "air sac". The sac is extremely developed and can take in several litters of air. Due to the drastic decrease of its in situ population, caused by illegal hunting and other reasons, the orangutan has been considered as an endangered species (IUCN - Appendix I) and its existence has been strictly protected by law (Fauna Protection Ordinance, 1931 - Stbl 134 and 226). Recently, reintroduction program has been considered as an effective approach to conserve the orangutan population in its in situ habitat. This program begins with the breeding program of the orangutan in the captive environment which is a simulated environment of its native habitat. The goal of captive breeding program is to bear the offspring of the orangutan which will be reintroduced to its native habitat later on, in healthy condition, free from infectious deseases, endo and ecto parasites and still bears its natural behavior. The Zoological Park would be the right institution to conduct the program. The captive (ex situ) breeding program of the orangutan has been being conducted by the Ragunan Zoological Park in Jakarta to study epidemiological, behavior, and other biological aspects of the orangutan in order to support the reintroduction program. Specifically, the study has examined and or investigated the medical records, feed and nutrition, behavior, tuberculin test, contraceptive procedure, normal electrocardiogram, normal hematology, clinical chemistry, caging contruction and management (include sanitation), preventive and curative disease treatment and raising procedure. The medical data, which has been collected for five years, indicated that the orangutan raised in the open cages was healthier than the one raised in the close cages. It was observed that the former group was rarely infected by any diseases. The investment of the open cage was more expensive than the close cage during construction period, but relatively very small cost was needed for maintenance in the long run. The air sacullitis case among the orangutan in Kalimantan has never been reported. This disease is a chronic disease. However, the case was reported among the orangutan raised in the foreign countries. It was reported that the case was caused by the Pseudomonas sp, Proteus sp and by Ischerechia call. These bacteria are not pathogen. The examination of air saculitis exudate derived from the orangutan raised in the Ragunan Zoo, has been sucsesful in isolating the Streptococcus pneumoniae. This bacteria is pathogen and anthropozoonosis to human and to other wild or domesticated animals.