Laboratory tests for chlamydial infection. Their role in epidemiological studies of trachoma and its control.

Abstract

The isolation and serial cultivation of chlamydial organisms from trachoma (Tang, Chang, Huang, and Wang, 1957; Collier and Sowa, I958) and from inclusion blennorrhoea or paratrachoma (Jones, Collier, and Smith, I959), together with the proof that these TRIC agents cause these diseases (Collier, Duke-Elder, and Jones, I958, i96o; Jones and Collier, I962) have opened the way to the development of a variety of laboratory tests that can indicate infection by Chlamydia, including those that cause trachoma and related syndromes of eye disease. Both the epidemiological study of trachoma and its control, and the individual clinical diagnosis of trachoma and other syndromes of TRIC agent infection of the eye or genital tract, have been severely hampered by the absence of sensitive diagnostic laboratory tests. There is now a variety of tests differing one from another in sensitivity and in the type of information they yield (Table I). It is now possible to provide, either for routine clinical purposes or for epidemiological studies, a service giving rapid and sensitive recognition of the chlamydial serotypes responsible (Jones, I973).

The detection ofChlamydia trachomatisby direct immunofluorescence in conjunctival smears from patients with trachoma and patients with ophthalmia neonatorum using a conjugated monoclonal antibody

“…It confirms the diagnosis in doubtful cases, gives a measure of the reservoir of infection in the community and is helpful in monitoring the effect of control programmes (Dawson, Jones & Tarizzo, 1981;Jones, 1974).…”

“…All these techniques are well suited to work under field conditions, but scraping the conjunctiva with a sharp metal blade is painful, frequently causes bleeding in patients with active trachoma, and is likely to lead to resentment and lack of co-operation among populations investigated. Isolation 84 D. C. W. MABEY AND S. BOOTH-MASON in irradiated or cycloheximide-treated McCoy cells is more sensitive than any of these techniques (Jones, 1974;Schachter et al 1978) and does not require conjunctival scrapings since cotton-wool swabs have been shown to yield as many positives as scrapings by this technique . It is therefore the method of choice at present.…”

Diagnosis and Assessment of Trachoma

“…Because these epitopes are common to all chlamydial species (59), the specificity of the test was low (230). Additionally, it had low sensitivity for ocular infections (108,214).…”

The microbial epidemiology of trachoma

“…The authors suggested that the differing serovars of some of the adults was probably a reflection of infection in their youth. The three exceptions of children in the 31 families were two with evidence of both B and C infections and one with serovar D. This latter finding along with reports of infections in Gambia with serovar D [16], in Iran with serovar D [13], in South Africa with serovars D/E, F and K [1], and serovar J in a Navajo Indian child with trachoma in the United States [12] may indicate that, given the appropriate epidemiologic milieu, serovars of C. trachomatis other than A, B, Ba, and C can cause endemic trachoma. In microbiologically monitored transmission trials in a village in southern Iran, only C. trachomatis isolates of the A and B serovars were found in the original survey [25,26].…”