Glossary of terms used in charts

This page is part of our report on The Carter Center.

Published: 2009

Onchocerciasis

The charts we include on our site measure the existence of this condition by considering the prevalence of microfilarie (in the eye or the skin), the presence of nodules, and the number of worms present per person.

• Measures of microfilarie (Mf) prevalence:
  • Prevalence of microfilarie in the antechamber of the eye (MfAC)
  • Prevalence of Mf in the skin
  • Mf carriers
• Measures of nodule prevalence:
  • Nodule prevalence
  • Nodule carriers
• Measures of the per person magnitude of infection:
  • Worm load
  • The community microfilarial load (CMFL), calculated as the geometric mean of the number of microfilariae per skin snip in adults 20 years and older.1
• Measurement of clinical manifestations:
  • Punctate keratitis: a lesion on the eye.2
  • Onchodermatitis: severe skin disease resulting from onchocerciass.3

Lymphatic filariasis

The charts we include on our site measure the existence of this condition by ICT positivity, thick smear results or mosquito infection results:

• ICT positivity: Immunochromatographic antigen card test (ICT) measures whether a person is infected, though not necessarily symptomatic, by a finger-stick sample of blood.4
• Thick smear results: A similar test to ICT, though these tests are less convenient as they must be conducted at night.5
• Mosquito infection results: The presence of infection among the mosquitoes that transmit the disease.

Schistosomiasis

Schistosomiasis is easily diagnosed by indicating the presence of blood in the urine, also known as hematuria.6

Sources

• The Carter Center's River Blindness Program Report. 2008. Available online at http://cartercenter.org/resources/pdfs/news/health_publications/river_b…, accessed 7/7/09.
• Summary of the Third Meeting of the ITFDE (II). 2002. Available online at http://www.cartercenter.org/documents/1181.pdf, accessed 7/7/09.

• 1

  Borsboom 2003, Pg 3

• 2

  http://emedicine.medscape.com/article/224309-overview, accessed 7/7/09

• 3

  http://emedicine.medscape.com/article/224309-overview, accessed 7/7/09

• 4

  "A new Immunochromatographic antigen card test (ICT) allows accurate rapid diagnosis based on a finger-stick sample of blood, which does not have to be taken at night." Summary of the Third Meeting of the ITFDE (II) 2002, Pg 2.

• 5

  "The infection rates in 2007 were compared with baseline values gathered in 1999-2003 in nine sentinel villages. Wuchereria bancrofti microfilariae in nocturnal thick smears decreased by 85% (Figure 41), from 9.8% in 2002-2003 to 0.7% in 2007 (the WHO threshold for elimination is for microfilaremia to be below 1%)." River Blindness Program Report 2008, Pg 65.

• 6

  "Up to now we have focused only on urinary schistosomiasis mapping since it is easily done using rapid diagnostic dipsticks for blood in urine (hematuria) caused by the parasite." River Blindness Program Report 2008, Pg 129.