Bacterial infections

Lymphogranuloma venereum

Occurrence:

Tropics and subtropics mainly

Organism:

Chlamydia trachomatis (serotypes L1—3)

Reservoir.

Humans

Transmission: Genital sexual contact, indirect

contact

Lymphogranuloma venereum (LGV) is one of a range of diseases caused by Chlamydia trachomatis (see p. 122). Unlike trachoma arid inclusion cöBc junctivitis (see p. 122) the serotypes of I'd. 1.2 amL.1.3 cause systemic disease rather than being fcsmctcd to the mucous membrane surface^/^

LABORATORY DIAGNOSIS

Stained smears of pus and other ] 'i&obglca material may show virus particles. The organism can b-

identified on culture in the yolk sacs of embryo-nated eggs. Serological tests become positive some 2-A weeks after the onset of the illness. A skin test, the Frei test, is available, but cross-reactions with other viral infections of the psittacosis group may occur depending on the purity of the antigen. It tends to remain positive for long periods.

EPIDEMIOLOGY

The infection is endemic in many parts of the tropics and subtropics.

Reservoir and transmission

The reservoir of infection is in humans, the source being the open lesions in patients with active disease. Transmission is mainly by sexual contact but also by indirect contact through contaminated clothing and other fomites.

Host factors

As with other sexually transmitted diseases, the sexual behaviour of the host is a major factor determining the distribution and spread of this infection. Recovery from a clinical attack does not confer immunity.

CONTROL

The main principles are as for other sexually transmitted diseases. The early stages of infection respond to antibiotics including doxycycline, erythromycin and tetracycline.

Soft chancre (chancroid)

Occurrence:

Tropics, especially seaports

Organism:

Haemophilus ducreyi

Reservoir.

Humans

Transmission:

Sexual contact, accidental

infection through non-sexual

contact

Control:

As for other sexually transmitted

diseases

Chemotherapy with antibiotics

CONTROL

genitalia (known as soft chancre in contrast to the hard chancre of syphilis). The inguinal lymph nodes become enlarged and may suppurate (buboes). Extragenital lesions may be found on the abdomen, fingers or other sites.

The incubation period is usually from 3 to 5 days but it may be very short (24 hours) where the lesion affects mucous membranes.

BACTERIOLOGY

The causative agent is Haemophilus ducreyi, a Gram-negative non-sporing bacillus.

EPIDEMIOLOGY

The infection occurs in many parts of the world, especially in tropical seaports.

Reservoir

The reservoir of infection is in human beings. The open lesions are the most important source of infection.

Transmission

Sexual contact is the usual mode of transmission but extragenital lesions may occur from nonsexual infection of children or accidental infection of doctors, nurses or other medical personnel who come into contact with infected lesions.

LABORATORY DIAGNOSIS

Microscopy of the stained smear of the exudate from ulcers or pus from the regional lymph nodes may show a mixed flora including Gram-negative bacilli. The organism can be isolated on culture of pus from the ulcer or bubo. An intradermal skin test is available but it does not differentiate active infections from previous attacks. Biopsy of the regional lymph nodes may also provide useful information.

CONTROL

This is an acute sexually transmitted infection which typically presents as a ragged painful ulcer on the

The general measures for the c litre: of sexually transmitted diseases apply to the problem of chancroid. Active infections usually respond to treatment with antibiotics.

Granuloma inguinale

Distribution:

Tropics and subtropics

Organism:

Calymmatobacterium granulomatis

Reservoir.

Humans

Transmission:

Contact, including sexual contact

Control:

General hygienic measures as for

other sexually transmitted

diseases

Transmission: Sexual contact, rarely through fomites

Eye infection during delivery Control: As for other sexually transmitted diseases

Toilet to the eyes of newborn babies

This is a chronic infection which presents with granulomatous lesions of the genitalia; regional lymph nodes may be affected and metastatic lesions occur. The incubation period is 1 week to 3 months.

ORGANISM

The aetiological agent is Calymmatobacterium gran-ulomatis (formerly Donovania granulomatis).

EPIDEMIOLOGY

The infection occurs in various parts of the tropics and subtropics, particularly in poorer communities. The reservoir of infection is in human beings. Transmission may be by sexual contact, but transmission through non-sexual contact also occurs.

LABORATORY DIAGNOSIS

Stained smears from active lesions show the typical Donovan bodies. A skin test is available and the complement fixation test can also be used in diagnosis.

CONTROL

General hygienic measures are important. Known cases should be treated with antibiotics (streptomycin, tetracycline, chloramphenicol or erythro-mycin). Contacts should be examined and treated if indicated.

In the male, this disease usually presents as an acute purulent urethritis with spread in some cases to involve the epididymis and testis. Late complications include urethral stricture, urethral sinuses and subfertility.

A high proportion (80-90%) of infected females are unaware of the infection; the others present with symptoms of urethritis and urethral or vaginal discharge. Complications in the female include bartholinitis, salpingitis, pyosalpinx and pelvic inflammatory disease. Late complications include subfertility resulting from tubal obstruction.

The incubation period is usually between 2 and 5 days, occasionally shorter (1 day), but may be as long as 2 weeks. It is usually notifiable nationally.

BACTERIOLOGY

Neisseria gonorrhoea is a Gram-negative diplococ-cus, with a characteristic bean shape. It dies rapidly outside the human body, being susceptible to drying and heat.

EPIDEMIOLOGY

The distribution is worldwide with particular concentrations at seaports, and in areas having a high concentration of migrant labour or military personnel.

Reservoir

The reservoir of infection is in human beings; the most important component is the female pool with asymptomatic infection.

Gonorrhoea

Occurrence:

Worldwide

Organism:

Neisseria gonorrhoeae

Reservoir:

Transmission of the infection is niqst^ by :

Sexual genital contact m Indirect contamination This lay product infection in prepubertal females. Vulvovaginitis may occur in a young girl who is infected sharing towels or other clothing with an infected older relative. Postpubertal girls do not become infected in this way; some cases of vulvovaginitis in young girls are the result of sexual contact with infected males.

■ Ophthalmia neonatorum This infection occurs in the course of delivering the baby of an infected mother.

Host factors

All persons are susceptible. There is no lasting immunity after recovery: repeated infections are common. As with other sexually transmitted diseases, the most important host factor is sexual behaviour.

LABORATORY DIAGNOSIS

Clinical diagnosis can be confirmed by bacteriological examination of stained smears of urethral discharge, cervical discharge or other infected material: the characteristic diplococci, some within pus cells, can be seen. The organisms can also be cultured on chocolate agar as a form of enrichment medium or on selective media such as the Thayer- Martin medium which contains antibiotics which suppress the growth of other organisms. Fluorescent antibody techniques are also available for diagnosis.

CONTROL

The control of gonorrhoea is posing a difficult problem in most parts of the world. Various factors have contributed to this difficulty:

■ revolutionary change in sexual mores;

■ replacement of the condom by effective contraceptive techniques which do not provide a mechanical barrier to infection;

■ emergence of drug resistant strains (Plate 37).

The control of gonorrhoea is based on the principles set out in the section on sexually transmitted diseases. Gonococcal ophthalmitis can be prevented by treating all infected pregnant women and by toilet to the eyes of all newborn babies. The latter consists of instilling one drop of 1% silver nitrate into the eyes of every newborn baby. Alternatively, tetracycline ointment may be used with the added advantage of protection against chlamydial infection.

Table 5.6: The trepanomatoses Venereal

Sexually transmitted syphilis

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