Toxoplasma, Entamoeba histolytica, Amoebic meningoencephalitis & keratitis


Relevant manifestations to consider further:

  • congenital – diagnosis – excellent recent guide 
  • reactivation in an immunocompromised (deficient cell-mediated immunity ) patient  such as someone with advanced HIV – then cerebral abscess (may be multiple), retinitis or pneumonitis (similar picture to pneumocystis) occur – direct tissue demonstration of tachyzoites required generally (PCR also possible).   Presumptive diagnosis usually made in HIV patient with cerebral abscess, usually after checking to confirm IgG seropositivity – therapeutic trial of antibiotic therapy then occurs – if no response then other differentials become more relevant – e.g. cerebral lymphoma.

Seroprevalence of anti-Toxoplasma gondii antibodies in HIV/AIDS patients and healthy blood donors at the Port Moresby General Hospital, Papua New Guinea.P N G Med J. 2012 Mar-Dec;55(1-4):88-93.   301 patients (181 HIV positive); overall antibody prevalence rate of 53% in the population and a significantly higher infection rate amongst HIV-positive patients.

Entamoeba histolytica

Note that if someone is a carrier (passes cysts of Entamoeba), then if they develop diarrhoea from some other cause, the cysts will form trophozoites – this does NOT mean the patient has amoebic dysentery!

Amoebic meningoencephalitis and keratitis

Primary amoebic meningoencephalitis in North Queensland: the paediatric experience. Med J Aust. 2016 Oct 3;205(7):325-8. Primary amoebic meningoencephalitis (PAM) is a fulminant, diffuse haemorrhagic meningoencephalitis caused by Naegleria fowleri, with an almost invariably fatal outcome. In Australia and the developed world, PAM remains a rare disease, although it is very likely that large numbers of cases go undetected in developing countries. N. fowleri is a thermophilic, free-living amoeba with a worldwide distribution. It is acquired when contaminated fresh water is flushed into the nose and penetrates the central nervous system via the cribriform plate. Clinical features are similar to those of bacterial meningitis, but it does not respond to standard therapy and rapid progression to death occurs in most cases. Some survivors have been reported; these patients received early treatment with amphotericin B in combination with a variety of other medications. Our review describes the local and worldwide experience of this disease and its clinical features, and discusses the associated diagnostic challenges. We hope that by detailing the local response to a recent case, and the outcomes of our public health campaign, we can improve the knowledge of this rare disease for doctors working in rural and remote Australia.

Primary amoebic meningoencephalitis in the Western Province. P N G Med J. 1991 Jun;34(2):87-9.  Six cases of primary amoebic meningoencephalitis were diagnosed and treated at the Balimo Health Centre between December 1986 and September 1988. This disease has not previously been reported in Papua New Guinea although from information derived from other studies it should be occurring in the lowlands of Papua New Guinea from time to time. Although less than optimum treatment was given to the early cases the case fatality rate in the series was only 66%. This compares very favorably with a case fatality rate of nearly 100% from other studies. Early diagnosis and prompt treatment should help to reduce mortality.

Strategies for the prevention of contact lens-related Acanthamoeba keratitis.  Ophthalmic Physiol Opt. 2016 Mar;36(2):77-92.  Acanthamoeba keratitis is a severe, often sight threatening, corneal infection which in Western countries is predominantly seen in daily wear of contact lenses. This review aims to summarise the pathobiology and epidemiology of contact lens-related Acanthamoeba keratitis, and to present strategies for prevention, particularly with respect to modifiable risk factors in contact lens wear.

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Coccidian enteric parasites- Cryptosporidium and Cyclospora

FERGUSON 2011 Coccidian enteric parasites  (includes references relevant to Nepal)

  • Rapid diagnostic tests for Cryptosporidium are effective- often combined with a giardia test.   However as the illness is self-limited in the immunocompetent, testing probably not relevant. Highly relevant for immunocompromised patients where treatment is required.
  •  Life cycle of Cryptosporidium.
  • Two PNG- associated references:

Seroepidemiology of cryptosporidiosis in children in Papua New Guinea and Australia.Groves VJ1, Lehmann D, Gilbert GLEpidemiol Infect. 1994 Dec;113(3):491-9.

Enzyme immunoassays (EIA) were used to measure serum antibodies to Cryptosporidium in four immunocompetent adults with recent proven cryptosporidial infection, 379 healthy children and 73 adult volunteers in Melbourne, Australia, and 205 children in Papua New Guinea (PNG) (47 healthy children; 158 with pneumonia). Antibodies peaked 3-6 weeks after infection and fell to baseline within a few months. A high level (5000 EIA units/ml) or a significant change between paired sera, of IgG or IgM, were taken as evidence of recent infection and found in 24% of PNG children and in 8% of children and 5% of adults in Melbourne. Among PNG children with pneumonia who had high cryptosporidial antibody levels, those with measles (6/8) were significantly more likely (P = 0.002) to have diarrhoea than the remainder (4/28). Symptomatic cryptosporidiosis may be associated with transient immune suppression due to viral infection. This study indicates that serological surveys can contribute to an understanding of the epidemiology of cryptosporidosis.

Cryptosporidium species in sheep and goats from Papua New Guinea. Exp Parasitol. 2014 Jun;141:134-7. 

Species of Cryptosporidium are extensively recognised as pathogens of domesticated livestock and poultry, companion animals, wildlife, and are a threat to public health. Little is known of the prevalence of Cryptosporidium spp. in humans, domesticated animals or wildlife in Papua New Guinea (PNG). The aim of the present study was to screen sheep and goats for Cryptosporidium using molecular tools. A total of 504 faecal samples were collected from sheep (n=276) and goats (n=228) in village, government and institutional farms in PNG. Samples were screened by nested PCR and genotyped at the 18S rRNA and at the 60kDa glycoprotein (gp60) loci. The overall prevalences were 2.2% for sheep (6/278) and 4.4% (10/228) for goats. The species/genotypes identified were Cryptosporidium hominis (subtype IdA15G1) in goats (n=6), Cryptosporidium parvum (subtypes IIaA15G2R1and IIaA19G4R1) in sheep (n=4) and in goats (n=2), Cryptosporidium andersoni (n=1) and Cryptosporidium scrofarum (n=1) in sheep, Cryptosporidium xiao (n=1) and Cryptosporidium rat genotype II (n=1) in goats. This is the first report of Cryptosporidium spp. identified in sheep and goats in PNG. Identification of Cryptosporidium in livestock warrants better care of farm animals to avoid contamination and illness in vulnerable population. The detection of zoonotic Cryptosporidium in livestock suggests these animals may serve as reservoirs for human infection.

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Plasmodium species (malaria)

Recent CPHL malaria workshop materials – make sure you have a copy and review same.

Short answer questions to guide your further reading: 

  1. What rapid diagnostic tests are in use and what is their performance?  Check the kit inserts and share what you find please.  Also visit WHO Malaria RDT resource page.
  2. What are the PNG-specific current malaria treatment guidelines? (not necessarily what is in the old STG)
  3. What are the expected changes to be found on fbc and film examination of a patient with malaria?
  4. Describe artemisinin resistance – incidence and impact – see this WHO page.
  5. Describe current progress towards malaria vaccines – yes! there is a candidate vaccine that works to prevent malaria in children – pilot implementation project in three countries at present.

Scan Pubmed to browse recent research on malaria published by PNG projects.  Select a paper for your next journal club!

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Infection control guidelines – Pacific Nations

PPHSN Infection Prevention and  Control Guidelines –  2010 

These are likely to be updated before too long.  They are produced by PICNet – Pacific regional Infection Control Network.

Updated PNG Infection Control Guidelines are expected soon.

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Hepatitis E- more important issues for Pacific nations

Please see this previously posted presentation from Prof. Josh Davis about HEV– an excellent overview – tells the Australian part of the story – endemicity in pigs (genotype 3) and local foodborne outbreaks.

The only survey of seroprevalence in the Pacific was published in 2014, referencing data acquired from Kiribati, PNG and Fiji 2003-5 – essential reading.  Overall 15% seroprevalence in PNG, higher in the highlands.  It references some data showing that genotype 3 has been found in pigs in New Caledonia.

Rapid testing reference referred today by Joe is here – an Italian study – almost all cases were genotype 1 which may make the tests less reliable in PNG.  Another good paper for your journal club.

As discussed, there will be an unknown morbidity occurring in PNG, especially in pregnant women and it is almost certain that a large zoonotic reservoir exists. Ripe for some proper research and important that local testing is established. 

According to WHO, a recombinant effective vaccine to prevent hepatitis E virus infection has been developed and is licensed in China, but is not yet available elsewhere.

PNG should coloured red! 

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“UTI” – Requiem for a Heavyweight – a landmark paper

A really important paper to consider closely – i will send on a PDF via email as general access not available.  This editorial from the BMJ is a worthwhile read as well.

AIMED - Let's talk about antibiotics

A recent paper, “Urinary Tract Infection”-Requiem for a Heavyweight  by Dr Thomas Finucaine skillfully unpacks many key issues, coupling this with a consideration of the emerging knowledge of the urinary microbiome and virome, suggesting that the term “UTI” might better be referred to as a “urinary dysbiosis”.  The paper is worth a detailed read – here is the start of the abstract –

“Urinary tract infection” (“UTI”) is an ambiguous, expansive, overused diagnosis that can lead to marked, harmful antibiotic overtreatment. “Significant bacteriuria,” central to most definitions of “UTI,” has little significance in identifying individuals who will benefit from treatment. “Urinary symptoms” are similarly uninformative. Neither criterion is well defined. Bacteriuria and symptoms remit and recur spontaneously. Treatment is standard for acute uncomplicated cystitis and common for asymptomatic bacteriuria, but definite benefits are few. Treatment for “UTI” in older adults with delirium and bacteriuria is widespread but no evidence supports…

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You are what you eat – or should our gut microbiome be considered an important body system in its own right?

AIMED - Let's talk about antibiotics

Guest posting: Assoc. Prof. Josh Davis,  Principal Research Fellow/NHMRC Career Development Fellow, Menzies School of Health Research, Senior Staff Specialist Infectious Diseases Physician, John Hunter Hospital, Conjoint Professor School of Medicine and Public Health, University of Newcastle

The diverse bacterial communities which live in our gastrointestinal tract (primary in the colon), are collectively known as the “gut microbiota” and their collective genes are termed the “microbiome“.  A majority of the bacterial species cannot cultivated and require direct molecular techniques to ennumerate them.  Consideration of the microbiome is extremely topical in many fields of health-related research. At the recent major annual meeting of the American Society for Microbiology (ASM Microbe), the gut microbiome had its own stream (no pun intended – and the colour coding wasn’t brown) within the conference program, containing scores of research presentations in this field. In fact, one conference delegate, science writer and microbiologist Ed Yong, insisted…

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Neisseria gonnorhoeae – brief review and data on AMR in PNG

A brief Neisseria gonorrhoeae update from our registrar Ian Marr at our regular bug of the week teaching round. We still culture it regularly from our samples – susceptibility testing is done at a reference laboratory. PCR diagnosis from early pass urine is the mainstay for most patients (main test method for C. trachomatis as well.

Please seek out this reference – here is the full text link.  Abstract below.   Good for a journal club.  I’ve not found anything more recent. Perhaps someone can check with PNGIMR and with Dr Valleley.  

P N G Med J. 2010 Mar-Jun;53(1-2):15-20.  Neisseria gonorrhoeae isolates from four centres in Papua New Guinea remain susceptible to amoxycillin-clavulanate therapy.  Toliman PJ1, Lupiwa T, Law GJ, Reeder JC, Siba PM.

Antibiotic-resistant strains of Neisseria gonorrhoeae have the potential to undermine treatment and control of gonorrhoea, which remains a highly prevalent sexually transmitted infection (STI) in Papua New Guinea (PNG). The standard treatment regimen for gonorrhoea in PNG based on amoxycillin and clavulanic acid (amoxycillin-clavulanate) was introduced about 15 years ago and there is some concern that over time circulating strains may have developed resistance to this therapy. To investigate this, N. gonorrhoeae isolates (n = 52) were collected from STI clinics in geographically representative centres in PNG and tested for their in vitro susceptibility to a range of antibiotics. All 52 isolates tested were found susceptible to amoxycillin-clavulanate, despite 40% (n = 21) being penicillinase producers and thus resistant to penicillin. These findings indicate that amoxycillin-clavulanate therapy remains an effective treatment for gonococcal infections in PNG, and support the maintenance of the present standard treatment for gonorrhoea in PNG.


  • WHO STD Laboratory Reference Manual – this is a good reference to go to for advice on key techniques – it is essential that we get a reliable culture system working again in PMGH for instance and this is a good starting point.
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WHO Core Components for Infection Control

Essential guidelines published last year by the WHO.  There is an excellent brief (2 minute) video review of the components. This is the single page info graphic:

Remember also to complete the 10 free Australian Commission on Safety and Quality in Healthcare short online learning modules for Infection Prevention and Control. Enroll here!

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Q fever and other rickettsia

This Q fever presentation from Professor Stephen Graves is worthwhile of review.  The presence of Q fever in PNG is likely but not proven as yet.   Dr Ak’s paper to be appended soon!

Also review this summary of laboratory diagnosis of rickettsial infection from Prof Graves.


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