Louse-borne diseases
流行性斑疹伤寒 （Epidemic typhus ） 普氏立克次体 （Rickettsia prowazekii）
战壕热(Trench fever) 五日立克次体（ Rochalimaea quintana ）
虱媒回归热（ Louse-borne relapsing fever） 包柔疏螺旋体（ Borrelia recurrentis）
Bed bug (臭虫)
Cimex hemipterus, 热带臭虫
Cimex lectularis, 温带臭虫
不完全变态
栖息在木质床榻的缝隙中，夜间吸血，群居
Cockroach (蜚蠊)
美洲大蠊
黑胸大蠊 德国小蠊
卵荚（鞘）
生活习性： 栖息于温暖及与食物、水近的场所，昼伏夜
出，分泌“信息素”，杂食性，“电脑害虫”
人体虱
Pediculosis capitis
Pththirus pubis (耻阴虱) , the crab louse, is more difficult to transmit and less common. It is associated almost exclusively with sexual transmission, and is rarely found outside the genital region.
➢ 鼠型斑疹伤寒
Rickettsia mooseri transmitted by Xenopsylla cheopis
➢ intermediate hosts of Hymenolepis
Louse (Pediculus)
• 2.5~4.2mm, dorsoventrally flattened • Prominent tarsal claw • Protuberance of tibia（胫突）and claws form gripping organ（攫握器）
multiplies and blocks the flea’s proventriculus (前胃). While the fleas feeds again, it is unable to engorge and is forced to regurgitate blood and the bacteria from the proventriculus into the host. Clinical manifestation: bubonic plague, pneumonic plague, septicemic plague
Harms to humans
❖ All stages and both sexes feed solely on blood
❖ Inject saliva into the wound; meanwhile feces are continually passed onto the skin ❖ Live in 29-32℃, RH 70% (on skin of host)
Pediculus humanus corporis (人体虱) and Pediculus humanus capitis (人头虱) are the two species that cause human infestations. They are transmitted from human to human by direct contact or via contaminated clothing, bedding and personal hygiene items (combs, brushes, etc.).
Medical arthropoda
Sand flies (白蛉)
• Very small (1.3-3.5 mm) • Hairy body • Wings held in a “V” above the body • Weak flying insects
Act as vector of Leishmaniasis
• Life cycle: 6-8 weeks • Seasonal existence: Jun-Sept • Activity area and distribution • Sensitive to insecticide
Fleas (蚤)
❖ 3mm and brown ❖ Laterally compressed and
meal • Excreting while feeding • Sensitive to body temperature
of host
Direct harms
❖ General nuisance: biting humans on exposed surfaces resulting in discomfort. Flea-bites induce pruritic（痒的） urticaria（风疹）;
wingless ❖ With 3 pairs of powerful
legs adapted for jumping, adults can jump about 70 cm vertically, 30 cm horizontally
Life cycle and habits
• Complete metamorphosis • Both sexes can taTunga penetrans, Tungiasis（潜蚤 病）
Disease transmission
➢ 鼠疫 (plague) (Yersinia pestis)
Vectors: 致痒蚤 (Pulex irritans);印鼠客蚤 (Xenopsylla cheopis) Mechanism: When takes a blood meal, the plague organism rapidly