Spatial and temporal variation in biting rates and parasite transmission potentials of onchocerciasis vectors in Ecuador

The influence of spatial and temporal factors on onchocerciasis transmission by Simulium exiguum s.l. and S. quadrivittatum in Ecuador was investigated to help develop sampling protocols for entomological surveillance of ivermectin programmes. Flies were collected in alternate months (November 1995-November 1996) at four sites each in the hyperendemic communities of San Miguel and El Tigre. A fixed-effects analysis of variance was used to explore the influence on vector abundance of locality, site, month and hour. Infectivity rates detected by dissection and PCR assays were compared. Simulium exiguum s.l. predominated at El Tigre (75%) whereas S. quadrivittatum prevailed at San Miguel (62%). Vector abundance was highest on river banks and outside houses. Biting and infection rates peaked from March to July. Hourly activity patterns were bimodal in S. exiguum but unimodal in S. quadrivittatum. Annual transmission potentials (ATP) for both species combined were 385 and 733 third stage larvae/person in San Miguel and El Tigre respectively, with S. exiguum accounting for 80% of the combined ATP at both localities. We recommend protocols that may maximize detection of parasite transmission. Infection rates thus obtained must be linked with vector density estimates to assess meaningfully host exposure as treatment progresses.

A molecular phylogeographic study based on DNA sequences from individual metacercariae of Paragonimus mexicanus from Guatemala and Ecuador

A molecular phylogeographic study of Paragonimus mexicanus collected from Guatemala and Ecuador was performed. Genomic DNA was extracted from individual metacercariae, and two gene regions (partial mitochondrial cytochrome c oxidase subunit 1 (CO1) and the second internal transcribed spacer of the nuclear ribosomal gene repeat (ITS2)) were amplified by the polymerase chain reaction (PCR). Sequences segregated in a phylogenetic tree according to their geographic origins. ITS2 sequences from Ecuador and Guatemala differed at only one site. Pairwise distances among CO1 sequences within a country were always lower than between countries. Nevertheless, genetic distances between countries were less than between geographical forms of P. westermani that have been suggested to be distinct species. This result suggests that populations from Guatemala and Ecuador are genetically differentiated perhaps at the level of subspecies.

Total reconstruction of the alar cartilages with a partially split septal cartilage graft

The alar cartilage is a unique structure that supports the tip of the nose, keeps the external valve open, and plays an important role in tip aesthetics. Very often the plastic surgeon needs to reconstruct this cartilage, as in secondary rhinoplasties when the lower lateral cartilage is overresected. Many authors have described cartilage grafts taken from the ear and septum, mounted and stitched in various manners, with some very good results. In patients with thin skin, though, any irregularity or distortion in the grafts becomes visible after a short time postoperatively. The authors present an alternative to reconstructing alar cartilage symmetrically using one graft. This graft is obtained by shaping septal cartilage in an "L" form, with a 135-deg angle (instead of a 90-deg angle) between its legs, and then splitting the smaller leg, obtaining a strut from the longer leg and two "lateral crura" from the shorter leg.

Treatment of the nasal hump with preservation of the cartilaginous framework

Classically, nasal hump reduction is based on the partial resection of the cartilages and bones of the nose, as it was described by Joseph almost a century ago. The cartilaginous portion of the hump consists of a single unity formed by the two upper lateral cartilages and the septal cartilage. During hump reduction in the classic rhinoplasty, this structure is slashed in three pieces, which is the main cause of irregularities, shadows, and pinchings over the long-term results. Late follow-ups of the classical hump removal often show an inverted V-shaped shadow on the dorsum secondary to the destruction of the osseous-cartilaginous transition. The angle and relation between the septal and upper lateral cartilages are reduced, which may compromise the functional aspect. The destruction of the unique anatomy of the cartilaginous hump is one of the main causes of this functional and aesthetic sequela. Here, we present a technique that preserves the cartilaginous framework of the nasal hump by lowering it through the resection of a strip of septum, avoiding the problems described above.

Successful control of onchocerciasis with community-based ivermectin distribution in the Rio Santiago focus in Ecuador

Onchocerciasis is a major blinding disease in equatorial Africa and Central and South America. Ivermectin is a safe and effective drug in the treatment of this disease and now forms the basis of disease control in most endemic areas. We report the findings of long-term control of this infection in the Río Santiago focus in Ecuador, between January 1990 and December 1996, using a strategy of giving ivermectin treatments biannually in hyperendemic communities and annually in meso- and hypoendemic communities. Ivermectin was administered by local health workers from each community. A high level of compliance to ivermectin was achieved, with 81.9% to 98.0% of those eligible receiving the drug at each treatment instance. The impact of ivermectin therapy was monitored using a cohort of 120 randomly selected infected individuals from 8 hyperendemic communities. The geometric mean microfilarial density of this group declined from 19.3 to 0 mf/mg over the 84-month observation period. Ivermectin had a significant impact on anterior segment ocular disease, acute onchodermatitis and sowda. The rate of infection of blackflies declined from 1.1% in 1989-0.08% in 1996, which is below the vectorial capacity of the Simulium vector and, as no new nodules were detected after 1994 and no children under 5 became infected over the observation period, it is likely that the transmission of this infection was interrupted in the study area.

Antibody isotypes, including IgG subclasses, in Ecuadorian patients with pulmonary paragonimiasis

An ELISA test was developed to detect Paragonimus-specific antibodies, including IgG subclasses, using P. mexicanus crude water-soluble antigens. The test was standardized to detect antibodies in sera of Ecuadorian patients with pulmonary paragonimiasis and negative controls from the endemic area. The detected mean levels of IgG (0.753, SEM: 0.074) and IgM (0.303, SEM: 0.033) were significantly elevated (P < 0.05). Within the IgG subclasses, IgG4 showed the highest detected mean level (0.365, SEM: 0.116) and the other three subclasses showed considerably lower mean levels (IgG1, 0.186 SEM: 0.06; IgG2, 0.046 SEM: 0.01; IgG3, 0.123 SEM: 0.047). The number of P. mexicanus eggs found in sputum of infected individuals showed a positive correlation with the level of antibodies detected for IgM, IgG and its subclasses (P < 0.001). The relevance of these findings in Ecuadorian patients suffering from pulmonary paragonimiasis is discussed.

Paragonimiasis in Ecuador: prevalence and geographical distribution of parasitisation of second intermediate hosts with Paragonimus mexicanus in Esmeraldas province

To determine whether the human cases of pulmonary paragonimiasis detected in the province of Esmeraldas were autochthonous a total of 1,457 freshwater crabs, species Hypolobocera aequatorialis, were collected from 45 different streams in 4 cantons to determine the rate of parasitisation with metacercariae of Paragonimus mexicanus. Some 28 (62.2%) streams were found to harbour parasitised crabs, with 76.5% of the streams in canton Quininde infected, followed by those in Muisne, 72.7%, Esmeraldas, 62.5% and Eloy Alfaro 22.2%. Of the 1,043 crabs studied from these 28 streams, 42.6% (444) were found to be parasitised with metacercariae: 45.1% of the crabs in the streams in the canton of Quininde, 43.9% in Muisne, 37.4% in Esmeraldas and 13.2% in Eloy Alfaro. There was a positive correlation between the crab parasitisation and the increasing size of their carapace. The results indicate that there is potential active transmission of disease in the four cantons in the province of Esmeraldas and that the human cases detected are probably autochthonous.

[Toxic shock syndrome after reduction mammaplasty: a case report]

The clinical features of the toxic shock syndrome are well established. It is rapidly developing disease and may be lethal if not recognized and treated in time. Once the syndrome was associated with the use of tampon by menstruating women. Recently this syndrome has been reported as due to Staphylococcus aureus infection. A severe case of toxic shock syndrome in a 18-years-old patient after reduction mammoplasty is reported, and the importance of an early diagnosis is emphasized.