The 2021 cases were from the Eastern Cape (nine), KwaZulu-Natal (six) and Limpopo (four) provinces.
SOUTH Africa has recorded its first human rabies case for 2022 after recording a total of 19 such cases in 2021.
According to the January 2022 National Institute for Communicable Diseases (NICD) communiqué, the 2021 cases were from the Eastern Cape (nine), KwaZulu-Natal (six) and Limpopo (four) provinces.
The NICD said the first case of 2022 was confirmed in a 4-year-old girl from the Eastern Cape.
The child was playing with a dog near her home in Gqeberha when the dog bit her on the lip on December 1, 2021.
“A month later the child was admitted to the hospital with fever, nausea, vomiting, headache, anorexia, sleeplessness, anxiety, confusion, delirium, seizures, agitation, localised pain/paraesthesia, autonomic instability, hypersalivation and hydrophobia,” the NICD said.
It said ante-mortem samples were collected for rabies investigation, and an RT-PCR test on a skin biopsy and cerebrospinal fluid (CSF) confirmed rabies. For ante-mortem testing, skin biopsies and saliva samples were taken at different time points (for example, collected on successive days) and CSF were tested.
The gold standard for rabies laboratory diagnosis is, however, the direct fluorescent antibody test (DFA) performed on impressions of post-mortem-collected brain samples. The brainstem and cerebellum are the preferred tissues.
“Post-mortem examinations and brain specimens are not always obtained for confirmatory testing, as in this case. This case is part of a rabies outbreak that has been ongoing in Nelson Mandela Bay and other Eastern Cape communities since early 2021,” the NICD said.
Additionally, a case was confirmed as a patient who contracted the disease in Lusaka, Zambia, but was hospitalised and died in Johannesburg.
“The 58-year-old man from Zambia was bitten on the arm by a suspected rabid dog in November 2021 in his home on the outskirts of Lusaka. The dog was killed and buried without any rabies tests being conducted. The patient reportedly received a tetanus booster vaccination and a rabies vaccine. Since the patient suffered a category III exposure, the administration of rabies immunoglobulin (RIG) was also required. The RIG was reportedly not available locally and had to be sourced from India, resulting in a six-day delay in administration,” the NICD said.
It said that in late December 2021 the patient was hospitalised in Lusaka with spasms, fits, autonomic nervous system instability and generalised pain. He was evacuated to South Africa, where he was hospitalised in Johannesburg in early January 2022. The differential diagnosis included tetanus and other causes of encephalitis, but rabies was considered a major risk in this case. A comprehensive ante-mortem laboratory investigation included a viral screen on CSF for usual viral pathogens and several tests for rabies including RT-PCR testing of several saliva samples, a skin biopsy sample and a CSF sample. The latter repeatedly tested negative. Serology performed on serial CSF samples indicated the presence of rabies specific IgG and IgM antibodies, which was considered supportive of the clinical diagnosis of rabies.
“Because the blood-brain barrier, as well as the blood-spinal cord barrier, limits the passage of vaccine-elicited neutralising antibodies from blood to CSF, the presence of rabies antibodies in the CSF, notably IgM antibodies, indicates rabies infection rather than an immune response to prophylaxis. A DFA test on post-mortem brain samples confirmed rabies.”
The NICD said rabies post-exposure prophylaxis (PEP) is considered safe and effective when delivered per guidelines.
“For the first case, reportedly no PEP was sought. Health education is crucial in communities affected by dog rabies,” the NICD said.
It said often interactions with dogs (and other animals) may be considered benign and the risk of rabies is not appreciated (for example with small wounds such as nicks or scratches). Rabies PEP must be delivered promptly following possible exposure. The longer the period between exposure and delivery of PEP the greater the risk for the virus infection to develop and spread to the central nervous system where it largely evades the immune system. Certain exposures are also associated with shorter incubation periods, these include exposures to the head and neck but also other highly innervated areas.
Pre-exposure prophylaxis (PrEP) provides critical protection against potential rabies exposures in occupational groups at high risk, for example animal health workers, and obviates the need for RIG in the event of potential rabies exposure.
Travellers and expatriates in countries where rabies is endemic and availability of rabies PEP, especially RIG, is likely to be limited or non-existent should consider PrEP. PrEP consists of two rabies vaccines on day 0 and day 7. The intramuscular route or intradermal route can be used, with the latter providing a cost-effective, dose-sparing option. In previously vaccinated persons, vaccine boosters, but no RIG, should be given on day 0 and day 3 and will be highly effective, even if the primary course of vaccines was 15 to 20 years previously.
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