Diagnosing AIDS and Emerging Infections in Resource-Limited Settings:
The Role of the Pathologist in Patient Care and Disease Surveillance
Section 10 -
Expert Referral Centres For HIV & Emerging Infection Pathology: The United Kingdom
The population of the UK is 60 million with a growing proportion of recent immigrants and many
travellers overseas. The total number of people with HIV is estimated at about 60,000, with one third of
them not knowing they have HIV infection. The single largest cause of death in those with HIV is late
presentation with HIV-related complications, the diagnosis of HIV being made only in the last illness
which is too severe to cure. Earlier diagnosis of HIV, including pre-symptomatic, would make the largest
contribution to improving the outcome and survival of those with HIV. Classical tropical infections are
common in the UK, with (eg) more than 2000 cases of falciparum malaria imported per annum. [see Health
Protection Agency website]
Whilst HIV and other infectious diseases are seen in all regions of the UK, there is significant
asymmetry in geographical distribution. Historically 65% of all HIV and imported tropical disease cases
are encountered in London and the south-east, whilst having only 20% of the total population.
Unsurprisingly, this is the area where pathological expertise is concentrated.
Disposition of cellular pathology in the UK
Cellular pathology in the UK is predominantly organised through the National Health Service and
universities, with a small but growing contribution from private laboratories. There are about 1300
senior pathologists employed by about 240 hospitals and 20 medical schools.
Increasingly, cellular pathology is becoming specialised with pathologists focussing on a small range
of diseases, all organ-based (eg gut, lung, skin, gynae, nervous system); the only exception is forensic
pathology. This specialisation is driven by the cancer networks and the development of tertiary cancer
centres for regions.
Infectious diseases is not a recognised subspeciality of histopathology, although infections occur
across all organ systems. The competence of histopathologists in evaluating infectious diseases varies
greatly and it is not considered as important as the correct diagnosis of cancer. Centres that
specialise in HIV or tropical/infectious diseases do not have designated pathology posts that focus on
these diseases, with appropriate funded time sessions.
Limited exception to this pattern are the pathologists who specialise in liver disease, who are
familiar with the hepatitis viruses; haemato-pathologists who know about EBV and HHV8 infection; and
neuropathologists who evaluate viral encephalitis and toxoplasmic encephalitis.
Tropical and infectious disease experience
The number of pathologists who have worked in resource-poor countries as part of their training is
less than it was 30 years ago, in part as training programmes have become more organised, output-driven,
and less flexible. As the older experienced pathologists retire, the pool of those with significant ID
experience is shrinking.
Autopsy experience in HIV disease is highly selective, as the infection is distributed predominantly
in the south east of the UK. The total number of HIV+ deaths is currently about 500pa. Few pathologists
have any significant experience. About half of deaths of HIV+ persons in UK are caused by
immunodeficiency; the other half are from other unrelated diseases, suicide, accident, drug overdose.
Because of fear of infection on the part of pathologists and mortuary technologists, the majority of
mortuaries in the UK do not accept cases with known or suspect hazard group 3 infections (including HIV,
TB, HCV). This leads to concentration of the activity in a smaller number of centres. There are
protocols for HIV (and other infectious disease) autopsy work on the Royal College of Pathologists
website [see Publications section].
A number of departments performed routine diagnostic histopathology for hospitals overseas (eg in
Africa) by post. This has provided material for experience and training. This activity has declined for
several reasons: overseas hospitals closed because of civil disturbance; some hospitals re-used the
central laboratory; UK hospitals raised the costs of such charity work until it became unsustainable; the
original UK pathologists who sustained it retired.
Infectious disease pathology expertise in the UK that covers the broad area of HIV disease, tropical
diseases, and possible emerging infections is thus limited. It is focussed on a very few individuals who
have taken an interest and become reference experts by reputation, on the back of their formal job which
usually does not include this expert activity. A typical single-handed London-based specialist will do
more than half of all the HIV autopsies that are performed in the UK, chair the annual
clinico-pathological reviews of all HIV-related pathology in the local regional HIV centres, and receive
a large number of postal referrals of ?HIV-related disease.
Referrals and charging
Traditionally, referring cases of expert advice on any aspect of cellular pathology, via blocks and
slides, has cost nothing to the sender apart from postage. Increasingly, hospital departments are
insisting that their consultant pathologists invoice the sender for the consultation. The usual fee is
about £250 ($475) depending on amount of immunostaining or molecular diagnostics required. To maintain
ID referral practice and expertises, it is important that such charges should be resisted. Also it
inhibits pathologists from sending problems to be evaluated.
In UK, the main advisory body on HIV is the British HIV Association (BHIVA). It functions to hold
conferences and produce guidelines and standards of care for those with HIV infection in the UK.
Clinically, HIV medicine is not yet recognised as a specialty differentiated from Genito-Urinary
medicine; it is combined within GU medicine in the Royal College of Physicians; it has a Diploma with the
Society of Apothecaries, but this diploma is not (yet) regarded as an essential to a senior clinical
appointment with an interest in HIV medicine. Thus, not surprisingly, there is no HIV subspecialty
within the Royal College of Pathologists either.
BHIVA guidelines do incorporate some pathology material (eg the Tuberculosis co-infection guidelines
[see website]) where the importance of autopsy analysis following death in those co-infected is
Because of more limited ID experience among the younger pathologists, they are going to have a sharper
learning curve than their seniors, when faced with diagnostic problems. There are few international
centres to which aspirant specialists could go for more experience: the USA AFIP is one, and the French
Institute Pasteur units constitute another. In the end, most such specialist learn from personal
experience and from diagnostic mistakes.
Links with overseas HIV and ID research centres is another means of acquiring experience. However, in
comparison with clinical medicine and microbiology, cellular pathology is not currently so much in demand
that resources at the home and overseas ends are available for such links. Perhaps this will change as
the importance of HIV and ID cellular pathology and diagnostics is appreciated in the growing HIV
Prospects for ID pathology in the UK
There is a planned modernisation of UK pathology, now being piloted in England & Wales. This
involves more centralisation of the high volume blood-based laboratory medicine sectors (haematology,
chemical pathology, microbiology). The impact on cellular pathology is not certain, but presumably will
continue the current slow amalgamation of smaller units and development of networks primarily based on
cancer diagnostics and management.
There is no reference to infectious disease pathology in any recent government plans concerning
clinical or laboratory medicine, and it is unlikely that cellular pathology will embrace ID as a
sub-specialty. This means that it will continue as before, with a small number of self-selected
individuals taking an interest. They will acquire experience through direct and referral practice. It
is unlikely that there will be central funding for cellular pathology ID expertise, on the grounds that
this has never happened before.
- UK HIV demographic data (March 2006) http://www.hpa.org.uk/infections/topics_az/hiv_and_sti/hiv/epidemiology/files/2006_Q1_Mar_HIV_Quarterlies.pdf
- BHIVA website: www.bhiva.org
- Royal College of Pathologists website: www.rcpath.org